From 570c1fd69fdfb9bcfd73bf8feb46abc68dadb2af Mon Sep 17 00:00:00 2001 From: nilsberglund-orleans <83530463+nilsberglund-orleans@users.noreply.github.com> Date: Tue, 28 Dec 2021 15:45:19 +0100 Subject: [PATCH] Add files via upload --- Parameters.md | 3782 +++++++++++++++++++++++++++++++------- Parameters_November21.md | 3751 +++++++++++++++++++++++++++++++++++++ 2 files changed, 6918 insertions(+), 615 deletions(-) create mode 100644 Parameters_November21.md diff --git a/Parameters.md b/Parameters.md index ab2640e..afaf75a 100644 --- a/Parameters.md +++ b/Parameters.md @@ -10,267 +10,9 @@ updated gradually. -### 12 November 21 - Classics revisited: Wave in an ellipse starting from a focus ### +### 28 December 21 - Let it snow: interface growth with molecular dynamics ### -**Program:** `wave_billiard.c` - -**Initial condition in function `animation()`:** `init_circular_wave(sqrt(LAMBDA*LAMBDA - 1.0), 0.0, phi, psi, xy_in);` - -``` -#define MOVIE 1 /* set to 1 to generate movie */ -#define DOUBLE_MOVIE 0 /* set to 1 to produce movies for wave height and energy simultaneously */ - -/* General geometrical parameters */ - -#define WINWIDTH 1280 /* window width */ -#define WINHEIGHT 720 /* window height */ - -#define NX 1280 /* number of grid points on x axis */ -#define NY 720 /* number of grid points on y axis */ - -#define XMIN -2.0 -#define XMAX 2.0 /* x interval */ -#define YMIN -1.125 -#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ - -#define JULIA_SCALE 1.0 /* scaling for Julia sets */ - -/* Choice of the billiard table */ - -#define B_DOMAIN 1 /* choice of domain shape, see list in global_pdes.c */ - -#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ - -#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ -#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ - -#define LAMBDA 1.5 /* parameter controlling the dimensions of domain */ -#define MU 1.0 /* parameter controlling the dimensions of domain */ -#define NPOLY 4 /* number of sides of polygon */ -#define APOLY 0.5 /* angle by which to turn polygon, in units of Pi/2 */ -#define MDEPTH 4 /* depth of computation of Menger gasket */ -#define MRATIO 3 /* ratio defining Menger gasket */ -#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ -#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ -#define FOCI 1 /* set to 1 to draw focal points of ellipse */ -#define NGRIDX 16 /* number of grid point for grid of disks */ -#define NGRIDY 20 /* number of grid point for grid of disks */ - -#define X_SHOOTER -0.2 -#define Y_SHOOTER -0.6 -#define X_TARGET 0.4 -#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ - -#define ISO_XSHIFT_LEFT -2.9 -#define ISO_XSHIFT_RIGHT 1.4 -#define ISO_YSHIFT_LEFT -0.15 -#define ISO_YSHIFT_RIGHT -0.15 -#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ - -/* You can add more billiard tables by adapting the functions */ -/* xy_in_billiard and draw_billiard below */ - -/* Physical parameters of wave equation */ - -#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ -#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ -#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ - -#define OMEGA 0.002 /* frequency of periodic excitation */ -#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ -#define COURANT 0.02 /* Courant number */ -#define COURANTB 0.02 /* Courant number in medium B */ -#define GAMMA 0.0 /* damping factor in wave equation */ -#define GAMMAB 5.0e-3 /* damping factor in wave equation */ -#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ -#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ -#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ -#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ -#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ -/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ -/* The physical damping coefficient is given by GAMMA/(DT)^2 */ -/* Increasing COURANT speeds up the simulation, but decreases accuracy */ -/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ - -/* Boundary conditions, see list in global_pdes.c */ - -#define B_COND 2 - -/* Parameters for length and speed of simulation */ - -// #define NSTEPS 500 /* number of frames of movie */ -#define NSTEPS 4200 /* number of frames of movie */ -#define NVID 40 /* number of iterations between images displayed on screen */ -#define NSEG 100 /* number of segments of boundary */ -#define INITIAL_TIME 0 /* time after which to start saving frames */ -#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ - -#define PAUSE 1000 /* number of frames after which to pause */ -#define PSLEEP 1 /* sleep time during pause */ -#define SLEEP1 1 /* initial sleeping time */ -#define SLEEP2 1 /* final sleeping time */ -#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ -#define END_FRAMES 100 /* number of still frames at end of movie */ - -/* Parameters of initial condition */ - -#define INITIAL_AMP 0.75 /* amplitude of initial condition */ -#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ -#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ - -/* Plot type, see list in global_pdes.c */ - -#define PLOT 0 - -#define PLOT_B 1 /* plot type for second movie */ - -/* Color schemes */ - -#define COLOR_PALETTE 11 /* Color palette, see list in global_pdes.c */ - -#define BLACK 1 /* background */ - -#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ - -#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ -#define SLOPE 0.25 /* sensitivity of color on wave amplitude */ -#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ -#define E_SCALE 120.0 /* scaling factor for energy representation */ - -#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ -#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ -#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ -#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ -#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ -#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ - -#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ -#define COLORBAR_RANGE 7.5 /* scale of color scheme bar */ -#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ - -#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ - -/* For debugging purposes only */ -#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ -#define VMAX 10.0 /* max value of wave amplitude */ - -``` - -### 11 November 21 - Stringer Bell's demise: trajectories in a Tokarsky room with a moving shooter ### - -**Program:** `particle_trajectory.c` - -**Initial condition in function `animation()`:** - -``` - x = -0.95 - 0.2*time; - y = 0.5 - 0.5*(1.0 - time); - alpha = argument(x + 0.95, y) - PI; - compute_trajectories_xy(x, y, alpha, DPI + alpha, configs, trajectory, traj_length); -``` - -``` -#define MOVIE 1 /* set to 1 to generate movie */ - -#define WINWIDTH 1280 /* window width */ -#define WINHEIGHT 720 /* window height */ - -#define XMIN -2.0 -#define XMAX 2.0 /* x interval */ -#define YMIN -1.125 -#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ - -#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ - -/* Choice of the billiard table, see global_particles.c */ - -#define B_DOMAIN 30 /* choice of domain shape */ - -#define CIRCLE_PATTERN 5 /* pattern of circles */ -#define POLYLINE_PATTERN 1 /* pattern of polyline */ - -#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ - -#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ -#define NMAXPOLY 1000 /* total number of sides of polygonal line */ -#define NCX 9 /* number of circles in x direction */ -#define NCY 20 /* number of circles in y direction */ -#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ -#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ - -#define LAMBDA 1.5 /* parameter controlling shape of domain */ -#define MU 0.02 /* second parameter controlling shape of billiard */ -#define FOCI 1 /* set to 1 to draw focal points of ellipse */ -#define NPOLY 4 /* number of sides of polygon */ -#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ -#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ -#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ -#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ - -#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ -#define DEBUG 0 /* draw trajectories, for debugging purposes */ - -/* Simulation parameters */ - -#define NPART 10000 /* number of particles */ -#define NPARTMAX 100000 /* maximal number of particles after resampling */ -#define TRAJ_LENGTH 48 /* length of trajectory */ -#define LMAX 0.01 /* minimal segment length triggering resampling */ -#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ -#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ -#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ -#define SHOWZOOM 1 /* set to 1 to show zoom on specific area */ -#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ - -#define NSTEPS 2000 /* number of frames of movie */ -#define TIME 2500 /* time between movie frames, for fluidity of real-time simulation */ -#define DPHI 0.00001 /* integration step */ -#define NVID 150 /* number of iterations between images displayed on screen */ - -/* Decreasing TIME accelerates the animation and the movie */ -/* For constant speed of movie, TIME*DPHI should be kept constant */ -/* However, increasing DPHI too much deterioriates quality of simulation */ -/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ -/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ - -/* Colors and other graphical parameters */ - -#define COLOR_PALETTE 14 /* Color palette, see list in global_pdes.c */ - -#define NCOLORS 64 /* number of colors */ -#define COLORSHIFT 0 /* hue of initial color */ -#define RAINBOW_COLOR 1 /* set to 1 to use different colors for all particles */ -#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ -#define NSEG 100 /* number of segments of boundary */ -#define LENGTH 0.03 /* length of velocity vectors */ -#define BILLIARD_WIDTH 2 /* width of billiard */ -#define PARTICLE_WIDTH 2 /* width of particles */ -#define FRONT_WIDTH 3 /* width of wave front */ - -#define BLACK 1 /* set to 1 for black background */ -#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ -#define OUTER_COLOR 270.0 /* color outside billiard */ -#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ -#define PAINT_EXT 1 /* set to 1 to paint exterior */ - -#define PAUSE 1000 /* number of frames after which to pause */ -#define PSLEEP 1 /* sleep time during pause */ -#define SLEEP1 1 /* initial sleeping time */ -#define SLEEP2 1000 /* final sleeping time */ - -``` - -### 10 November 21 - The power of Inti: Four waves in a rotating four-sided parabolic resonator ### - -**Program:** `wave_billiard_rotate.c` - -**Initial condition in function `animation()`:** -``` - init_circular_wave(0.35, 0.35, phi, psi, xy_in); - add_circular_wave(-1.0, -0.35, 0.35, phi, psi, xy_in); - add_circular_wave(1.0, -0.35, -0.35, phi, psi, xy_in); - add_circular_wave(-1.0, 0.35, -0.35, phi, psi, xy_in); -``` +**Program:** `lennardjones.c` ``` #define MOVIE 1 /* set to 1 to generate movie */ @@ -281,38 +23,341 @@ updated gradually. #define WINWIDTH 1280 /* window width */ #define WINHEIGHT 720 /* window height */ -#define NX 1280 /* number of grid points on x axis */ -#define NY 720 /* number of grid points on y axis */ +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define INITXMIN -2.0 +#define INITXMAX 2.0 /* x interval for initial condition */ +#define INITYMIN -0.8 +#define INITYMAX 1.125 /* y interval for initial condition */ + +#define CIRCLE_PATTERN 8 /* pattern of circles, see list in global_ljones.c */ + +#define INTERACTION 1 /* particle interaction, see list in global_ljones.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 100 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define PDISC_DISTANCE 5.0 /* minimal distance in Poisson disc process, controls density of particles */ +#define PDISC_CANDIDATES 100 /* number of candidates in construction of Poisson disc process */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.015 /* parameter controlling radius of particles */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 32 /* number of grid point for grid of disks */ +#define NGRIDY 26 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +/* Boundary conditions, see list in global_ljones.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 3600 /* number of frames of movie */ +#define NVID 250 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + + +/* Plot type, see list in global_ljones.c */ + +#define PLOT 1 +#define PLOT_B 3 /* plot type for second movie */ + + +/* Color schemes */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_ljones.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 1 /* choice of color scheme, see list in global_ljones.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.5 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -50.0 /* amplitude of variation of hue for color scheme C_HUE */ + +/* particle properties */ + +#define PARTICLE_HUE_MIN 330.0 /* color of original particle */ +#define PARTICLE_HUE_MAX 30.0 /* color of saturated particle */ +#define PARTICLE_EMAX 2.0e1 /* max energy for particle to survive */ + +#define RANDOM_RADIUS 0 /* set to 1 for random circle radius */ +#define MOVE_PARTICLES 1 /* set to 1 for mobile particles */ +#define INERTIA 1 /* set to 1 for taking inertia into account */ +#define DT_PARTICLE 2.0e-6 /* time step for particle displacement */ +#define KREPEL 10.0 /* constant in repelling force between particles */ +#define EQUILIBRIUM_DIST 4.0 /* Lennard-Jones equilibrium distance */ +#define REPEL_RADIUS 20.0 /* radius in which repelling force acts (in units of particle radius) */ +#define DAMPING 1.5e5 /* damping coefficient of particles */ +#define PARTICLE_MASS 1.0 /* mass of particle of radius MU */ +#define V_INITIAL 5.0 /* initial velocity range */ +#define SIGMA 5.0 /* noise intensity in thermostat */ +#define BETA 1.0e-2 /* initial inverse temperature */ +#define MU_XI 0.1 /* friction constant in thermostat */ +#define KSPRING_BOUNDARY 1.0e5 /* confining harmonic potential outside simulation region */ +#define NBH_DIST_FACTOR 4.5 /* radius in which to count neighbours */ +#define GRAVITY 300.0 /* gravity acting on all particles */ + +#define INCREASE_BETA 1 /* set to 1 to increase BETA during simulation */ +#define BETA_FACTOR 1.0e1 /* factor by which to change BETA during simulation */ +#define N_TOSCILLATIONS 0.25 /* number of temperature oscillations in BETA schedule */ + +#define INCREASE_KREPEL 0 /* set to 1 to increase KREPEL during simulation */ +#define KREPEL_FACTOR 1000.0 /* factor by which to change KREPEL during simulation */ + +#define PART_AT_BOTTOM 1 /* set to 1 to include "seed" particles at bottom */ +#define MASS_PART_BOTTOM 10000.0 /* mass of particles at bottom */ +#define NPART_BOTTOM 100 /* number of particles at the bottom */ + +#define ADD_PARTICLES 1 /* set to 1 to add particles */ +#define ADD_TIME 50 /* time at which to add first particle */ +#define ADD_PERIOD 7 /* time interval between adding further particles */ +#define SAFETY_FACTOR 3.0 /* no particles are added at distance less than MU*SAFETY_FACTOR of other particles */ + +#define FLOOR_FORCE 0 /* set to 1 to limit force on particle to FMAX */ +#define FMAX 2.0e10 /* maximal force */ + +#define HASHX 32 /* size of hashgrid in x direction */ +#define HASHY 18 /* size of hashgrid in y direction */ +#define HASHMAX 100 /* maximal number of particles per hashgrid cell */ +#define HASHGRID_PADDING 0.1 /* padding of hashgrid outside simulation window */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 1 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 27 December 21 - Molecular dynamics with pentagonal symmetry, a representation with atomic bonds ### + +**Program:** `lennardjones.c` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ #define XMIN -2.0 #define XMAX 2.0 /* x interval */ #define YMIN -1.125 #define YMAX 1.125 /* y interval for 9/16 aspect ratio */ -#define JULIA_SCALE 1.0 /* scaling for Julia sets */ - /* Choice of the billiard table */ -#define B_DOMAIN 32 /* choice of domain shape, see list in global_pdes.c */ +// #define B_DOMAIN 20 /* choice of domain shape, see list in global_ljones.c */ -#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ +#define CIRCLE_PATTERN 8 /* pattern of circles, see list in global_ljones.c */ + +#define INTERACTION 3 /* particle interaction, see list in global_ljones.c */ #define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ -#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NPOISSON 100 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define PDISC_DISTANCE 2.5 /* minimal distance in Poisson disc process, controls density of particles */ +#define PDISC_CANDIDATES 100 /* number of candidates in construction of Poisson disc process */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ -#define LAMBDA 0.0 /* parameter controlling the dimensions of domain */ -#define MU 0.9 /* parameter controlling the dimensions of domain */ -#define NPOLY 4 /* number of sides of polygon */ -#define APOLY -0.02 /* angle by which to turn polygon, in units of Pi/2 */ +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.02 /* parameter controlling radius of particles */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */ #define MDEPTH 4 /* depth of computation of Menger gasket */ #define MRATIO 3 /* ratio defining Menger gasket */ #define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ #define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ #define FOCI 1 /* set to 1 to draw focal points of ellipse */ -#define NGRIDX 16 /* number of grid point for grid of disks */ -#define NGRIDY 20 /* number of grid point for grid of disks */ +#define NGRIDX 32 /* number of grid point for grid of disks */ +#define NGRIDY 26 /* number of grid point for grid of disks */ -#define ROTATION 0.0015 /* rotation angle per frame */ +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +/* Boundary conditions, see list in global_ljones.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 3600 /* number of frames of movie */ +#define NVID 150 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + + +/* Plot type, see list in global_ljones.c */ + +#define PLOT 3 + +/* Color schemes */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_ljones.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 1 /* choice of color scheme, see list in global_ljones.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.5 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -50.0 /* amplitude of variation of hue for color scheme C_HUE */ + +/* particle properties */ + +#define PARTICLE_HUE_MIN 330.0 /* color of original particle */ +#define PARTICLE_HUE_MAX 30.0 /* color of saturated particle */ +#define PARTICLE_EMAX 2.0e1 /* max energy for particle to survive */ + +#define RANDOM_RADIUS 0 /* set to 1 for random circle radius */ +#define MOVE_PARTICLES 1 /* set to 1 for mobile particles */ +#define INERTIA 1 /* set to 1 for taking inertia into account */ +#define DT_PARTICLE 2.0e-6 /* time step for particle displacement */ +#define KREPEL 20.0 /* constant in repelling force between particles */ +#define EQUILIBRIUM_DIST 5.0 /* Lennard-Jones equilibrium distance */ +#define REPEL_RADIUS 20.0 /* radius in which repelling force acts (in units of particle radius) */ +#define DAMPING 1.5e5 /* damping coefficient of particles */ +#define PARTICLE_MASS 1.0 /* mass of particle of radius MU */ +#define V_INITIAL 5.0 /* initial velocity range */ +#define SIGMA 5.0 /* noise intensity in thermostat */ +#define BETA 5.0e-3 /* initial inverse temperature */ +#define MU_XI 0.1 /* friction constant in thermostat */ +#define KSPRING_BOUNDARY 1.0e5 /* confining harmonic potential outside simulation region */ +#define NBH_DIST_FACTOR 4.5 /* radius in which to count neighbours */ + +#define INCREASE_BETA 1 /* set to 1 to increase BETA during simulation */ +#define BETA_FACTOR 5.0e2 /* factor by which to change BETA during simulation */ +#define N_TOSCILLATIONS 2.5 /* number of temperature oscillations in BETA schedule */ + +#define INCREASE_KREPEL 0 /* set to 1 to increase KREPEL during simulation */ +#define KREPEL_FACTOR 1000.0 /* factor by which to change KREPEL during simulation */ + +#define ADD_PARTICLES 0 /* set to 1 to add particles */ +#define ADD_TIME 300 /* time at which to add first particle */ +#define ADD_PERIOD 2000 /* time interval between adding further particles */ + +#define FLOOR_FORCE 0 /* set to 1 to limit force on particle to FMAX */ +#define FMAX 2.0e10 /* maximal force */ + +#define HASHX 32 /* size of hashgrid in x direction */ +#define HASHY 18 /* size of hashgrid in y direction */ +#define HASHMAX 100 /* maximal number of particles per hashgrid cell */ +#define HASHGRID_PADDING 0.1 /* padding of hashgrid outside simulation window */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 1 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 26 December 21 - Wave protection comparison 12: Triangles pointing right vs randomly rotated triangles ### + +**Program:** `wave_comparison.c` + +**Initial condition in function `animation()`:** `int_planar_wave_comp(XMIN + 0.015, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1920 /* window width */ +#define WINHEIGHT 1000 /* window height */ + +#define NX 1920 /* number of grid points on x axis */ +#define NY 1000 /* number of grid points on y axis */ +#define YMID 500 /* mid point of display */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.0729 +#define YMAX 1.0729 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 40 /* choice of domain shape, see list in global_pdes.c */ +#define B_DOMAIN_B 40 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 1 /* pattern of circles, see list in global_pdes.c */ +#define CIRCLE_PATTERN_B 1 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ +#define RANDOM_POLY_ANGLE_B 1 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 0.8 /* parameter controlling the dimensions of domain */ +#define MU 0.04665361 /* parameter controlling the dimensions of domain */ +#define MUB 0.04665361 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define APOLY_B 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 20 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ #define X_SHOOTER -0.2 #define Y_SHOOTER -0.6 @@ -331,20 +376,20 @@ updated gradually. /* Physical parameters of wave equation */ #define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ -#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ -#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ -#define OMEGA 0.002 /* frequency of periodic excitation */ -#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define OMEGA 0.0 /* frequency of periodic excitation */ +#define AMPLITUDE 0.025 /* amplitude of periodic excitation */ #define COURANT 0.02 /* Courant number */ -#define COURANTB 0.02 /* Courant number in medium B */ -#define GAMMA 0.0 /* damping factor in wave equation */ -#define GAMMAB 5.0e-3 /* damping factor in wave equation */ +#define COURANTB 0.004 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 1.0e-8 /* damping factor in wave equation */ #define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ -#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ -#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ -#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ -#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +#define GAMMA_TOPBOT 1.0e-6 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ /* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ /* The physical damping coefficient is given by GAMMA/(DT)^2 */ /* Increasing COURANT speeds up the simulation, but decreases accuracy */ @@ -352,81 +397,82 @@ updated gradually. /* Boundary conditions, see list in global_pdes.c */ -#define B_COND 2 +#define B_COND 3 /* Parameters for length and speed of simulation */ -#define NSTEPS 2600 /* number of frames of movie */ -#define NVID 50 /* number of iterations between images displayed on screen */ +#define NSTEPS 3500 /* number of frames of movie */ +#define NVID 25 /* number of iterations between images displayed on screen */ #define NSEG 100 /* number of segments of boundary */ -#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define INITIAL_TIME 150 /* time after which to start saving frames */ +#define COMPUTE_ENERGIES 1 /* set to 1 to compute and print energies */ #define BOUNDARY_WIDTH 2 /* width of billiard boundary */ -#define PAUSE 1000 /* number of frames after which to pause */ +#define PAUSE 1000 /* number of frames after which to pause */ #define PSLEEP 1 /* sleep time during pause */ #define SLEEP1 1 /* initial sleeping time */ -#define SLEEP2 1 /* final sleeping time */ -#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define SLEEP2 1 /* final sleeping time */ #define END_FRAMES 100 /* number of still frames at end of movie */ /* Parameters of initial condition */ #define INITIAL_AMP 0.75 /* amplitude of initial condition */ -#define INITIAL_VARIANCE 0.00025 /* variance of initial condition */ -#define INITIAL_WAVELENGTH 0.03 /* wavelength of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.02 /* wavelength of initial condition */ /* Plot type, see list in global_pdes.c */ -#define PLOT 0 - -#define PLOT_B 1 /* plot type for second movie */ +#define PLOT 4 /* Color schemes */ -#define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ +#define COLOR_PALETTE 13 /* Color palette, see list in global_pdes.c */ #define BLACK 1 /* background */ #define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ #define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ -#define SLOPE 0.2 /* sensitivity of color on wave amplitude */ +#define SLOPE 0.5 /* sensitivity of color on wave amplitude */ #define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ -#define E_SCALE 100.0 /* scaling factor for energy representation */ +#define E_SCALE 2000.0 /* scaling factor for energy representation */ +#define LOG_SCALE 1.5 /* scaling factor for energy log representation */ +#define LOG_SHIFT 1.0 /* shift of colors on log scale */ #define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ #define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ #define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ #define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ -#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ -#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -220.0 /* amplitude of variation of hue for color scheme C_HUE */ #define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ -#define COLORBAR_RANGE 7.5 /* scale of color scheme bar */ +#define COLORBAR_RANGE 100.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ #define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ -#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ /* For debugging purposes only */ #define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ -#define VMAX 10.0 /* max value of wave amplitude */ +#define VMAX 5.0 /* max value of wave amplitude */ ``` -### 9 November 21 - Particles stating off center in a parabolic resonator ### -**Program:** `particle_billiard.c` +### 25 December 21 - Mystery billiard 12 ### -**Initial condition in function `animation()`:** `init_drop_config(0.03, 0.02, 0.0, DPI, configs);` +**Program:** `mystery_billiard.c` (variant of `particle_billiard.c`) + +**Initial condition in function `animation()`:** `init_drop_config(0.0, -0.7, -0.1, 0.1, configs); ` ``` #define MOVIE 1 /* set to 1 to generate movie */ -#define WINWIDTH 720 /* window width */ +#define WINWIDTH 1280 /* window width */ #define WINHEIGHT 720 /* window height */ -#define XMIN -1.125 -#define XMAX 1.125 /* x interval */ +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ #define YMIN -1.125 #define YMAX 1.125 /* y interval for 9/16 aspect ratio */ @@ -434,26 +480,27 @@ updated gradually. /* Choice of the billiard table, see global_particles.c */ -#define B_DOMAIN 15 /* choice of domain shape */ +#define B_DOMAIN 30 /* choice of domain shape */ #define CIRCLE_PATTERN 1 /* pattern of circles */ -#define POLYLINE_PATTERN 1 /* pattern of polyline */ +#define POLYLINE_PATTERN 7 /* pattern of polyline */ #define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ -#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ -#define NMAXPOLY 1000 /* total number of sides of polygonal line */ +#define NMAXCIRCLES 10000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 10000 /* total number of sides of polygonal line */ #define NCX 30 /* number of circles in x direction */ #define NCY 20 /* number of circles in y direction */ #define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ #define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ +#define SDEPTH 4 /* Sierpinski gastket depth */ -#define LAMBDA 0.0 /* parameter controlling shape of domain */ -#define MU 1.0 /* second parameter controlling shape of billiard */ +#define LAMBDA 1.8 /* parameter controlling shape of domain */ +#define MU 0.01 /* second parameter controlling shape of billiard */ #define FOCI 1 /* set to 1 to draw focal points of ellipse */ -#define NPOLY 4 /* number of sides of polygon */ +#define NPOLY 6 /* number of sides of polygon */ #define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ -#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_BILLIARD 0 /* set to 1 to draw billiard */ #define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ #define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ @@ -462,7 +509,7 @@ updated gradually. /* Simulation parameters */ -#define NPART 20000 /* number of particles */ +#define NPART 2000 /* number of particles */ #define NPARTMAX 100000 /* maximal number of particles after resampling */ #define LMAX 0.01 /* minimal segment length triggering resampling */ #define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ @@ -472,10 +519,10 @@ updated gradually. #define PRINT_PARTICLE_NUMBER 0 /* set to 1 to print number of particles */ #define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ -#define NSTEPS 1350 /* number of frames of movie */ +#define NSTEPS 4825 /* number of frames of movie */ #define TIME 1500 /* time between movie frames, for fluidity of real-time simulation */ -#define DPHI 0.00001 /* integration step */ -#define NVID 150 /* number of iterations between images displayed on screen */ +#define DPHI 0.0000075 /* integration step */ +#define NVID 250 /* number of iterations between images displayed on screen */ /* Decreasing TIME accelerates the animation and the movie */ /* For constant speed of movie, TIME*DPHI should be kept constant */ @@ -485,9 +532,9 @@ updated gradually. /* Colors and other graphical parameters */ -#define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ +#define COLOR_PALETTE 14 /* Color palette, see list in global_pdes.c */ -#define NCOLORS 16 /* number of colors */ +#define NCOLORS 16 /* number of colors */ #define COLORSHIFT 0 /* hue of initial color */ #define RAINBOW_COLOR 0 /* set to 1 to use different colors for all particles */ #define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ @@ -507,10 +554,11 @@ updated gradually. #define PSLEEP 1 /* sleep time during pause */ #define SLEEP1 1 /* initial sleeping time */ #define SLEEP2 1000 /* final sleeping time */ +#define FINALFRAMES 100 /* number of still frames at the end */ ``` -### 8 November 21 - Chaotic waves in a diamond resonator ### +### 24 December 21 - Waves in a seven-pointed star ### **Program:** `wave_billiard.c` @@ -522,46 +570,47 @@ updated gradually. /* General geometrical parameters */ -#define WINWIDTH 1280 /* window width */ -#define WINHEIGHT 720 /* window height */ +#define WINWIDTH 1920 /* window width */ +#define WINHEIGHT 1030 /* window height */ -#define NX 1280 /* number of grid points on x axis */ -#define NY 720 /* number of grid points on y axis */ +#define NX 1920 /* number of grid points on x axis */ +#define NY 1030 /* number of grid points on y axis */ #define XMIN -2.0 #define XMAX 2.0 /* x interval */ -#define YMIN -1.125 -#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ +#define YMIN -1.0329 +#define YMAX 1.1129 /* y interval for 9/16 aspect ratio */ #define JULIA_SCALE 1.0 /* scaling for Julia sets */ /* Choice of the billiard table */ -#define B_DOMAIN 4 /* choice of domain shape, see list in global_pdes.c */ +#define B_DOMAIN 42 /* choice of domain shape, see list in global_pdes.c */ -#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ +#define CIRCLE_PATTERN 2 /* pattern of circles or polygons, see list in global_pdes.c */ #define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ #define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 1 /* set to 1 to randomize angle of polygons */ -#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ -#define MU 0.5 /* parameter controlling the dimensions of domain */ -#define NPOLY 4 /* number of sides of polygon */ -#define APOLY 0.5 /* angle by which to turn polygon, in units of Pi/2 */ -#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define LAMBDA 1.1 /* parameter controlling the dimensions of domain */ +#define MU 0.4 /* parameter controlling the dimensions of domain */ +#define NPOLY 14 /* number of sides of polygon */ +#define APOLY -1.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 5 /* depth of computation of Menger gasket */ #define MRATIO 3 /* ratio defining Menger gasket */ #define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ #define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ #define FOCI 1 /* set to 1 to draw focal points of ellipse */ -#define NGRIDX 16 /* number of grid point for grid of disks */ -#define NGRIDY 20 /* number of grid point for grid of disks */ +#define NGRIDX 10 /* number of grid point for grid of disks */ +#define NGRIDY 12 /* number of grid point for grid of disks */ #define X_SHOOTER -0.2 #define Y_SHOOTER -0.6 #define X_TARGET 0.4 #define Y_TARGET 0.7 /* shooter and target positions in laser fight */ -#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_LEFT -2.9 #define ISO_XSHIFT_RIGHT 1.4 #define ISO_YSHIFT_LEFT -0.15 #define ISO_YSHIFT_RIGHT -0.15 @@ -578,10 +627,10 @@ updated gradually. #define OMEGA 0.002 /* frequency of periodic excitation */ #define AMPLITUDE 1.0 /* amplitude of periodic excitation */ -#define COURANT 0.02 /* Courant number */ -#define COURANTB 0.02 /* Courant number in medium B */ +#define COURANT 0.04 /* Courant number */ +#define COURANTB 0.01 /* Courant number in medium B */ #define GAMMA 0.0 /* damping factor in wave equation */ -#define GAMMAB 5.0e-3 /* damping factor in wave equation */ +#define GAMMAB 1.0e-6 /* damping factor in wave equation */ #define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ #define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ #define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ @@ -594,47 +643,48 @@ updated gradually. /* Boundary conditions, see list in global_pdes.c */ -#define B_COND 2 +#define B_COND 3 /* Parameters for length and speed of simulation */ -#define NSTEPS 2300 /* number of frames of movie */ -#define NVID 40 /* number of iterations between images displayed on screen */ +#define NSTEPS 2100 /* number of frames of movie */ +#define NVID 25 /* number of iterations between images displayed on screen */ #define NSEG 100 /* number of segments of boundary */ #define INITIAL_TIME 0 /* time after which to start saving frames */ -#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ +#define BOUNDARY_WIDTH 3 /* width of billiard boundary */ #define PAUSE 1000 /* number of frames after which to pause */ #define PSLEEP 1 /* sleep time during pause */ #define SLEEP1 1 /* initial sleeping time */ #define SLEEP2 1 /* final sleeping time */ #define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ -#define END_FRAMES 100 /* number of still frames at end of movie */ +#define END_FRAMES 50 /* number of still frames at end of movie */ /* Parameters of initial condition */ #define INITIAL_AMP 0.75 /* amplitude of initial condition */ -#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ #define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ /* Plot type, see list in global_pdes.c */ -#define PLOT 0 +#define PLOT 1 -#define PLOT_B 1 /* plot type for second movie */ +#define PLOT_B 0 /* plot type for second movie */ /* Color schemes */ -#define COLOR_PALETTE 15 /* Color palette, see list in global_pdes.c */ +#define COLOR_PALETTE 12 /* Color palette, see list in global_pdes.c */ #define BLACK 1 /* background */ #define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ #define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ -#define SLOPE 0.25 /* sensitivity of color on wave amplitude */ +#define SLOPE 0.5 /* sensitivity of color on wave amplitude */ #define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ -#define E_SCALE 120.0 /* scaling factor for energy representation */ +#define E_SCALE 150.0 /* scaling factor for energy representation */ +#define LOG_SCALE 2.5 /* scaling factor for energy log representation */ #define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ #define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ @@ -644,7 +694,8 @@ updated gradually. #define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ #define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ -#define COLORBAR_RANGE 7.5 /* scale of color scheme bar */ +#define COLORBAR_RANGE 6.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 10.0 /* scale of color scheme bar for 2nd part */ #define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ #define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ @@ -655,11 +706,297 @@ updated gradually. ``` -### 7 November 21 - Don't s̶h̶u̶t̶ shoot me down (part 2): Particles with trails in a Tokarsky room ### +### 23 December 21 - Freezing and melting at the molecular scale: A representation with atomic bonds ### + +**Program:** `lennardjones.c` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +/* Choice of the billiard table */ + +#define CIRCLE_PATTERN 8 /* pattern of circles, see list in global_ljones.c */ + +#define INTERACTION 1 /* particle interaction, see list in global_ljones.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 100 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define PDISC_DISTANCE 3.25 /* minimal distance in Poisson disc process, controls density of particles */ +#define PDISC_CANDIDATES 100 /* number of candidates in construction of Poisson disc process */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.015 /* parameter controlling radius of particles */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 32 /* number of grid point for grid of disks */ +#define NGRIDY 26 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +/* Boundary conditions, see list in global_ljones.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 5500 /* number of frames of movie */ +#define NVID 150 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + + +/* Plot type, see list in global_ljones.c */ + +#define PLOT 3 + +/* Color schemes */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_ljones.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 1 /* choice of color scheme, see list in global_ljones.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.5 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -50.0 /* amplitude of variation of hue for color scheme C_HUE */ + +/* particle properties */ + +#define PARTICLE_HUE_MIN 330.0 /* color of original particle */ +#define PARTICLE_HUE_MAX 30.0 /* color of saturated particle */ +#define PARTICLE_EMAX 2.0e1 /* max energy for particle to survive */ + +#define RANDOM_RADIUS 0 /* set to 1 for random circle radius */ +#define MOVE_PARTICLES 1 /* set to 1 for mobile particles */ +#define INERTIA 1 /* set to 1 for taking inertia into account */ +#define DT_PARTICLE 2.0e-6 /* time step for particle displacement */ +#define KREPEL 100.0 /* constant in repelling force between particles */ +#define EQUILIBRIUM_DIST 4.0 /* Lennard-Jones equilibrium distance */ +#define REPEL_RADIUS 20.0 /* radius in which repelling force acts (in units of particle radius) */ +#define DAMPING 1.5e5 /* damping coefficient of particles */ +#define PARTICLE_MASS 1.0 /* mass of particle of radius MU */ +#define V_INITIAL 5.0 /* initial velocity range */ +#define SIGMA 5.0 /* noise intensity in thermostat */ +#define BETA 5.0e-3 /* initial inverse temperature */ +#define MU_XI 0.1 /* friction constant in thermostat */ +#define KSPRING_BOUNDARY 1.0e5 /* confining harmonic potential outside simulation region */ +#define NBH_DIST_FACTOR 5.0 /* radius in which to count neighbours */ + +#define INCREASE_BETA 1 /* set to 1 to increase BETA during simulation */ +#define BETA_FACTOR 5.0e2 /* factor by which to change BETA during simulation */ +#define N_TOSCILLATIONS 4.5 /* number of temperature oscillations in BETA schedule */ + +#define INCREASE_KREPEL 0 /* set to 1 to increase KREPEL during simulation */ +#define KREPEL_FACTOR 1000.0 /* factor by which to change KREPEL during simulation */ + +#define ADD_PARTICLES 0 /* set to 1 to add particles */ +#define ADD_TIME 300 /* time at which to add first particle */ +#define ADD_PERIOD 2000 /* time interval between adding further particles */ + +#define FLOOR_FORCE 0 /* set to 1 to limit force on particle to FMAX */ +#define FMAX 2.0e10 /* maximal force */ + +#define HASHX 32 /* size of hashgrid in x direction */ +#define HASHY 18 /* size of hashgrid in y direction */ +#define HASHMAX 100 /* maximal number of particles per hashgrid cell */ +#define HASHGRID_PADDING 0.1 /* padding of hashgrid outside simulation window */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 1 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 22 December 21 - An attempt at growing a quasicrystal ### + +**Program:** `lennardjones.c` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define CIRCLE_PATTERN 8 /* pattern of circles, see list in global_ljones.c */ + +#define INTERACTION 3 /* particle interaction, see list in global_ljones.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 100 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define PDISC_DISTANCE 2.5 /* minimal distance in Poisson disc process, controls density of particles */ +#define PDISC_CANDIDATES 100 /* number of candidates in construction of Poisson disc process */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.02 /* parameter controlling radius of particles */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 32 /* number of grid point for grid of disks */ +#define NGRIDY 26 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +/* Boundary conditions, see list in global_ljones.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 4800 /* number of frames of movie */ +#define NVID 150 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + + +/* Plot type, see list in global_ljones.c */ + +#define PLOT 1 + +/* Color schemes */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_ljones.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 1 /* choice of color scheme, see list in global_ljones.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -50.0 /* amplitude of variation of hue for color scheme C_HUE */ + +/* particle properties */ + +#define PARTICLE_HUE_MIN 330.0 /* color of original particle */ +#define PARTICLE_HUE_MAX 30.0 /* color of saturated particle */ +#define PARTICLE_EMAX 2.0e1 /* max energy for particle to survive */ + +#define RANDOM_RADIUS 0 /* set to 1 for random circle radius */ +#define MOVE_PARTICLES 1 /* set to 1 for mobile particles */ +#define INERTIA 1 /* set to 1 for taking inertia into account */ +#define DT_PARTICLE 2.0e-6 /* time step for particle displacement */ +#define KREPEL 20.0 /* constant in repelling force between particles */ +#define EQUILIBRIUM_DIST 5.0 /* Lennard-Jones equilibrium distance */ +#define REPEL_RADIUS 20.0 /* radius in which repelling force acts (in units of particle radius) */ +#define DAMPING 1.5e5 /* damping coefficient of particles */ +#define PARTICLE_MASS 1.0 /* mass of particle of radius MU */ +#define V_INITIAL 10.0 /* initial velocity range */ +#define SIGMA 5.0 /* noise intensity in thermostat */ +#define BETA 2.0e-3 /* initial inverse temperature */ +#define MU_XI 0.1 /* friction constant in thermostat */ +#define KSPRING_BOUNDARY 1.0e5 /* confining harmonic potential outside simulation region */ +#define NBH_DIST_FACTOR 4.0 /* radius in which to count neighbours */ + +#define INCREASE_BETA 1 /* set to 1 to increase BETA during simulation */ +#define BETA_FACTOR 1.0e3 /* factor by which to change BETA during simulation */ +#define N_TOSCILLATIONS 0.5 /* number of temperature oscillations in BETA schedule */ + +#define INCREASE_KREPEL 0 /* set to 1 to increase KREPEL during simulation */ +#define KREPEL_FACTOR 1000.0 /* factor by which to change KREPEL during simulation */ + +#define ADD_PARTICLES 0 /* set to 1 to add particles */ +#define ADD_TIME 300 /* time at which to add first particle */ +#define ADD_PERIOD 2000 /* time interval between adding further particles */ + +#define FLOOR_FORCE 0 /* set to 1 to limit force on particle to FMAX */ +#define FMAX 2.0e10 /* maximal force */ + +#define HASHX 32 /* size of hashgrid in x direction */ +#define HASHY 18 /* size of hashgrid in y direction */ +#define HASHMAX 100 /* maximal number of particles per hashgrid cell */ +#define HASHGRID_PADDING 0.1 /* padding of hashgrid outside simulation window */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 1 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 21 December 21 - Trajectory of a single particle in an unilluminable room without right angles ### **Program:** `particle_billiard.c` -**Initial condition in function `animation()`:** `init_drop_config(-0.95, 0.0, -0.1, -0.1 + DPI, configs);` +**Initial condition in function `animation()`:** +``` + alphamax = 2.50949; + init_drop_config(x_shooter, y_shooter, alphamax, alphamax + DPI, configs); +``` ``` #define MOVIE 1 /* set to 1 to generate movie */ @@ -679,21 +1016,22 @@ updated gradually. #define B_DOMAIN 30 /* choice of domain shape */ #define CIRCLE_PATTERN 1 /* pattern of circles */ -#define POLYLINE_PATTERN 1 /* pattern of polyline */ +#define POLYLINE_PATTERN 6 /* pattern of polyline */ #define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ -#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ -#define NMAXPOLY 1000 /* total number of sides of polygonal line */ +#define NMAXCIRCLES 100000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 100000 /* total number of sides of polygonal line */ #define NCX 30 /* number of circles in x direction */ #define NCY 20 /* number of circles in y direction */ #define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ #define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ +#define SDEPTH 1 /* Sierpinski gastket depth */ -#define LAMBDA 1.5 /* parameter controlling shape of domain */ -#define MU 0.0035 /* second parameter controlling shape of billiard */ +#define LAMBDA 0.8 /* parameter controlling shape of domain */ +#define MU 0.0025 /* second parameter controlling shape of billiard */ #define FOCI 1 /* set to 1 to draw focal points of ellipse */ -#define NPOLY 4 /* number of sides of polygon */ +#define NPOLY 6 /* number of sides of polygon */ #define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ #define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ #define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ @@ -704,20 +1042,21 @@ updated gradually. /* Simulation parameters */ -#define NPART 16 /* number of particles */ +#define NPART 1 /* number of particles */ #define NPARTMAX 100000 /* maximal number of particles after resampling */ #define LMAX 0.01 /* minimal segment length triggering resampling */ #define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ #define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ #define SHOWTRAILS 1 /* set to 1 to keep trails of the particles */ #define SHOWZOOM 1 /* set to 1 to show zoom on specific area */ -#define PRINT_PARTICLE_NUMBER 1 /* set to 1 to print number of particles */ +#define PRINT_PARTICLE_NUMBER 0 /* set to 1 to print number of particles */ +#define PRINT_COLLISION_NUMBER 1 /* set to 1 to print number of collisions */ #define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ -#define NSTEPS 3000 /* number of frames of movie */ +#define NSTEPS 9000 /* number of frames of movie */ #define TIME 1500 /* time between movie frames, for fluidity of real-time simulation */ #define DPHI 0.00001 /* integration step */ -#define NVID 150 /* number of iterations between images displayed on screen */ +#define NVID 300 /* number of iterations between images displayed on screen */ /* Decreasing TIME accelerates the animation and the movie */ /* For constant speed of movie, TIME*DPHI should be kept constant */ @@ -729,14 +1068,14 @@ updated gradually. #define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ -#define NCOLORS 64 /* number of colors */ +#define NCOLORS 32 /* number of colors */ #define COLORSHIFT 0 /* hue of initial color */ -#define RAINBOW_COLOR 1 /* set to 1 to use different colors for all particles */ +#define RAINBOW_COLOR 0 /* set to 1 to use different colors for all particles */ #define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ #define NSEG 100 /* number of segments of boundary */ #define LENGTH 0.015 /* length of velocity vectors */ #define BILLIARD_WIDTH 2 /* width of billiard */ -#define PARTICLE_WIDTH 2 /* width of particles */ +#define PARTICLE_WIDTH 3 /* width of particles */ #define FRONT_WIDTH 3 /* width of wave front */ #define BLACK 1 /* set to 1 for black background */ @@ -752,11 +1091,593 @@ updated gradually. ``` -### 6 November 21 - Wave amplitude and average energy in homophonic drums ### +### 20 December 21 - Freezing and melting of particles with anisotropic Lennard-Jones interaction ### + +**Program:** `lennardjones.c` + + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +/* Choice of the billiard table */ + +// #define B_DOMAIN 20 /* choice of domain shape, see list in global_ljones.c */ + +#define CIRCLE_PATTERN 8 /* pattern of circles, see list in global_ljones.c */ + +#define INTERACTION 2 /* particle interaction, see list in global_ljones.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 100 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define PDISC_DISTANCE 3.5 /* minimal distance in Poisson disc process */ +#define PDISC_CANDIDATES 100 /* number of candidates in construction of Poisson disc process */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.015 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 32 /* number of grid point for grid of disks */ +#define NGRIDY 26 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +/* Boundary conditions, see list in global_ljones.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 2775 /* number of frames of movie */ +#define NVID 150 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + + +/* Plot type, see list in global_ljones.c */ + +#define PLOT 1 + +/* Color schemes */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_ljones.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 1 /* choice of color scheme, see list in global_ljones.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -50.0 /* amplitude of variation of hue for color scheme C_HUE */ + +/* particle properties */ + +#define PARTICLE_HUE_MIN 330.0 /* color of original particle */ +#define PARTICLE_HUE_MAX 30.0 /* color of saturated particle */ +#define PARTICLE_EMAX 2.0e1 /* max energy for particle to survive */ + +#define RANDOM_RADIUS 0 /* set to 1 for random circle radius */ +#define MOVE_PARTICLES 1 /* set to 1 for mobile particles */ +#define INERTIA 1 /* set to 1 for taking inertia into account */ +#define DT_PARTICLE 2.0e-6 /* time step for particle displacement */ +#define KREPEL 10.0 /* constant in repelling force between particles */ +#define EQUILIBRIUM_DIST 5.0 /* Lennard-Jones equilibrium distance */ +#define REPEL_RADIUS 20.0 /* radius in which repelling force acts (in units of particle radius) */ +#define DAMPING 1.5e5 /* damping coefficient of particles */ +#define PARTICLE_MASS 1.0 /* mass of particle of radius MU */ +#define V_INITIAL 10.0 /* initial velocity range */ +#define SIGMA 5.0 /* noise intensity in thermostat */ +#define BETA 1.0e-3 /* initial inverse temperature */ +#define MU_XI 0.1 /* friction constant in thermostat */ +#define KSPRING_BOUNDARY 1.0e5 /* confining harmonic potential outside simulation region */ +#define NBH_DIST_FACTOR 4.5 /* radius in which to count neighbours */ + +#define INCREASE_BETA 1 /* set to 1 to increase BETA during simulation */ +#define BETA_FACTOR 1.0e2 /* factor by which to change BETA during simulation */ +#define N_TOSCILLATIONS 2 /* number of temperature oscillations in BETA schedule */ + +#define INCREASE_KREPEL 0 /* set to 1 to increase KREPEL during simulation */ +#define KREPEL_FACTOR 1000.0 /* factor by which to change KREPEL during simulation */ + +#define ADD_PARTICLES 0 /* set to 1 to add particles */ +#define ADD_TIME 300 /* time at which to add first particle */ +#define ADD_PERIOD 2000 /* time interval between adding further particles */ + +#define FLOOR_FORCE 0 /* set to 1 to limit force on particle to FMAX */ +#define FMAX 2.0e10 /* maximal force */ + +#define HASHX 32 /* size of hashgrid in x direction */ +#define HASHY 18 /* size of hashgrid in y direction */ +#define HASHMAX 100 /* maximal number of particles per hashgrid cell */ +#define HASHGRID_PADDING 0.1 /* padding of hashgrid outside simulation window */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 1 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 19 December 21 - Wave protection comparison 11: triangles on a triangular grid vs triangles on a square grid ### + +**Program:** `wave_comparison.c` + +**Initial condition in function `animation()`:** `int_planar_wave_comp(XMIN + 0.015, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1920 /* window width */ +#define WINHEIGHT 1030 /* window height */ + +#define NX 1920 /* number of grid points on x axis */ +#define NY 1030 /* number of grid points on y axis */ +#define YMID 500 /* mid point of display */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.0729 +#define YMAX 1.0729 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 40 /* choice of domain shape, see list in global_pdes.c */ +#define B_DOMAIN_B 40 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 0 /* pattern of circles, see list in global_pdes.c */ +#define CIRCLE_PATTERN_B 1 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 0.8 /* parameter controlling the dimensions of domain */ +#define MU 0.04665361 /* parameter controlling the dimensions of domain */ +#define MUB 0.04665361 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define APOLY_B 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 20 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -1.65 +#define ISO_XSHIFT_RIGHT 0.4 +#define ISO_YSHIFT_LEFT -0.05 +#define ISO_YSHIFT_RIGHT -0.05 +#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.0 /* frequency of periodic excitation */ +#define AMPLITUDE 0.025 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.004 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 1.0e-8 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-6 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 2500 /* number of frames of movie */ +#define NVID 25 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 150 /* time after which to start saving frames */ +#define COMPUTE_ENERGIES 1 /* set to 1 to compute and print energies */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.02 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 4 + +/* Color schemes */ + +#define COLOR_PALETTE 13 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.5 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 2000.0 /* scaling factor for energy representation */ +#define LOG_SCALE 1.5 /* scaling factor for energy log representation */ +#define LOG_SHIFT 1.0 /* shift of colors on log scale */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -220.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 100.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 5.0 /* max value of wave amplitude */ + +``` + +### 18 December 21 - Grain boundary dynamics under temperature cycling in a system with Lennard-Jones interaction ### + +**Program:** `lennardjones.c` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 20 /* choice of domain shape, see list in global_ljones.c */ + +#define CIRCLE_PATTERN 8 /* pattern of circles, see list in global_ljones.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 100 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.015 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 15 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +/* Boundary conditions, see list in global_ljones.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +// #define NSTEPS 4000 /* number of frames of movie */ +#define NSTEPS 6500 /* number of frames of movie */ +#define NVID 150 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + + +/* Plot type, see list in global_ljones.c */ + +#define PLOT 1 + +/* Color schemes */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_ljones.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 1 /* choice of color scheme, see list in global_ljones.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 2500.0 /* scaling factor for energy representation */ +#define LOG_SCALE 2.0 /* scaling factor for energy log representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -50.0 /* amplitude of variation of hue for color scheme C_HUE */ + +/* particle properties */ + +#define PARTICLE_HUE_MIN 330.0 /* color of original particle */ +#define PARTICLE_HUE_MAX 30.0 /* color of saturated particle */ +#define PARTICLE_EMAX 2.0e1 /* max energy for particle to survive */ + +#define RANDOM_RADIUS 0 /* set to 1 for random circle radius */ +#define MOVE_PARTICLES 1 /* set to 1 for mobile particles */ +#define INERTIA 1 /* set to 1 for taking inertia into account */ +#define DT_PARTICLE 2.0e-6 /* time step for particle displacement */ +#define KREPEL 100.0 /* constant in repelling force between particles */ +#define EQUILIBRIUM_DIST 4.0 /* Lennard-Jones equilibrium distance */ +#define REPEL_RADIUS 20.0 /* radius in which repelling force acts (in units of particle radius) */ +#define DAMPING 1.5e5 /* damping coefficient of particles */ +#define PARTICLE_MASS 1.0 /* mass of particle of radius MU */ +#define V_INITIAL 5.0 /* initial velocity range */ +#define SIGMA 5.0 /* noise intensity in thermostat */ +#define BETA 5.0e-3 /* initial inverse temperature */ +#define MU_XI 0.1 /* friction constant in thermostat */ +#define KSPRING_BOUNDARY 1.0e5 /* confining harmonic potential outside simulation region */ +#define NBH_DIST_FACTOR 5.0 /* radius in which to count neighbours */ + +#define INCREASE_BETA 1 /* set to 1 to increase BETA during simulation */ +#define BETA_FACTOR 5.0e2 /* factor by which to change BETA during simulation */ + +#define INCREASE_KREPEL 0 /* set to 1 to increase KREPEL during simulation */ +#define KREPEL_FACTOR 1000.0 /* factor by which to change KREPEL during simulation */ + +#define FLOOR_FORCE 0 /* set to 1 to limit force on particle to FMAX */ +#define FMAX 2.0e18 /* maximal force */ + +#define HASHX 32 /* size of hashgrid in x direction */ +#define HASHY 18 /* size of hashgrid in y direction */ +#define HASHMAX 100 /* maximal number of particles per hashgrid cell */ +#define HASHGRID_PADDING 0.1 /* padding of hashgrid outside simulation window */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 1 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 17 December 21 - Video #300: Waves in a star-shaped domain ### **Program:** `wave_billiard.c` -**Initial condition in function `animation()`:** `init_circular_wave_xplusminus(startleft[0], startleft[1], startright[0], startright[1], phi, psi, xy_in);` +**Initial condition in function `animation()`:** `` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 1 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1920 /* window width */ +#define WINHEIGHT 1080 /* window height */ + +#define NX 1920 /* number of grid points on x axis */ +#define NY 1080 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 42 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 2 /* pattern of circles or polygons, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 1 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 1.0 /* parameter controlling the dimensions of domain */ +#define MU 0.025 /* parameter controlling the dimensions of domain */ +#define NPOLY 128 /* number of sides of polygon */ +#define APOLY 0.33333333333333333 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 5 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 10 /* number of grid point for grid of disks */ +#define NGRIDY 12 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.04 /* Courant number */ +#define COURANTB 0.01 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 1.0e-6 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 3450 /* number of frames of movie */ +#define NVID 25 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 50 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 0 + +#define PLOT_B 1 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 13 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.5 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 150.0 /* scaling factor for energy representation */ +#define LOG_SCALE 2.5 /* scaling factor for energy log representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 6.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 10.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + + +### 16 December 21 - Waves in a unilluminable room without right angles ### + +**Program:** `wave_billiard.c` + +**Initial condition in function `animation()`:** `init_circular_wave(polyline[85].x, polyline[85].y, phi, psi, xy_in);` ``` #define MOVIE 1 /* set to 1 to generate movie */ @@ -779,24 +1700,25 @@ updated gradually. /* Choice of the billiard table */ -#define B_DOMAIN 38 /* choice of domain shape, see list in global_pdes.c */ +#define B_DOMAIN 36 /* choice of domain shape, see list in global_pdes.c */ -#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ +#define CIRCLE_PATTERN 2 /* pattern of circles or polygons, see list in global_pdes.c */ #define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ #define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 1 /* set to 1 to randomize angle of polygons */ -#define LAMBDA 1.5 /* parameter controlling the dimensions of domain */ -#define MU 0.5 /* parameter controlling the dimensions of domain */ -#define NPOLY 4 /* number of sides of polygon */ -#define APOLY 0.5 /* angle by which to turn polygon, in units of Pi/2 */ -#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define LAMBDA 0.8 /* parameter controlling the dimensions of domain */ +#define MU 0.2 /* parameter controlling the dimensions of domain */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.33333333333333333 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 5 /* depth of computation of Menger gasket */ #define MRATIO 3 /* ratio defining Menger gasket */ #define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ #define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ #define FOCI 1 /* set to 1 to draw focal points of ellipse */ -#define NGRIDX 16 /* number of grid point for grid of disks */ -#define NGRIDY 20 /* number of grid point for grid of disks */ +#define NGRIDX 10 /* number of grid point for grid of disks */ +#define NGRIDY 12 /* number of grid point for grid of disks */ #define X_SHOOTER -0.2 #define Y_SHOOTER -0.6 @@ -821,9 +1743,9 @@ updated gradually. #define OMEGA 0.002 /* frequency of periodic excitation */ #define AMPLITUDE 1.0 /* amplitude of periodic excitation */ #define COURANT 0.02 /* Courant number */ -#define COURANTB 0.02 /* Courant number in medium B */ +#define COURANTB 0.01 /* Courant number in medium B */ #define GAMMA 0.0 /* damping factor in wave equation */ -#define GAMMAB 5.0e-3 /* damping factor in wave equation */ +#define GAMMAB 1.0e-6 /* damping factor in wave equation */ #define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ #define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ #define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ @@ -836,12 +1758,12 @@ updated gradually. /* Boundary conditions, see list in global_pdes.c */ -#define B_COND 2 +#define B_COND 3 /* Parameters for length and speed of simulation */ -#define NSTEPS 3600 /* number of frames of movie */ -#define NVID 40 /* number of iterations between images displayed on screen */ +#define NSTEPS 3750 /* number of frames of movie */ +#define NVID 35 /* number of iterations between images displayed on screen */ #define NSEG 100 /* number of segments of boundary */ #define INITIAL_TIME 0 /* time after which to start saving frames */ #define BOUNDARY_WIDTH 2 /* width of billiard boundary */ @@ -851,32 +1773,33 @@ updated gradually. #define SLEEP1 1 /* initial sleeping time */ #define SLEEP2 1 /* final sleeping time */ #define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ -#define END_FRAMES 100 /* number of still frames at end of movie */ +#define END_FRAMES 50 /* number of still frames at end of movie */ /* Parameters of initial condition */ #define INITIAL_AMP 0.75 /* amplitude of initial condition */ #define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ -#define INITIAL_WAVELENGTH 0.02 /* wavelength of initial condition */ +#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ /* Plot type, see list in global_pdes.c */ #define PLOT 0 -#define PLOT_B 3 /* plot type for second movie */ +#define PLOT_B 5 /* plot type for second movie */ /* Color schemes */ -#define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ +#define COLOR_PALETTE 11 /* Color palette, see list in global_pdes.c */ #define BLACK 1 /* background */ #define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ #define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ -#define SLOPE 0.25 /* sensitivity of color on wave amplitude */ +#define SLOPE 0.5 /* sensitivity of color on wave amplitude */ #define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ -#define E_SCALE 150.0 /* scaling factor for energy representation */ +#define E_SCALE 250.0 /* scaling factor for energy representation */ +#define LOG_SCALE 2.5 /* scaling factor for energy log representation */ #define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ #define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ @@ -886,8 +1809,9 @@ updated gradually. #define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ #define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ -#define COLORBAR_RANGE 7.5 /* scale of color scheme bar */ -#define ROTATE_COLOR_SCHEME 1 /* set to 1 to draw color scheme horizontally */ +#define COLORBAR_RANGE 6.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 10.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ #define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ @@ -897,113 +1821,167 @@ updated gradually. ``` -### 5 November 21 - Don’t s̶h̶u̶t̶ shoot me down: Particles in a Tokarsky unilluminable room ### -**Program:** `particle_billiard.c` +### 15 December 21 - Inserting an atom in a crystal ### -**Initial condition in function `animation()`:** `init_drop_config(-0.95, 0.0, PI, 3.0*PI, configs);` +**Program:** `lennardjones.c` ``` #define MOVIE 1 /* set to 1 to generate movie */ -#define WINWIDTH 1280 /* window width */ +/* General geometrical parameters */ + +#define WINWIDTH 720 /* window width */ #define WINHEIGHT 720 /* window height */ -#define XMIN -2.0 -#define XMAX 2.0 /* x interval */ +#define XMIN -1.125 +#define XMAX 1.125 /* x interval */ #define YMIN -1.125 #define YMAX 1.125 /* y interval for 9/16 aspect ratio */ -#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ -/* Choice of the billiard table, see global_particles.c */ +/* Choice of the billiard table */ -#define B_DOMAIN 30 /* choice of domain shape */ +#define B_DOMAIN 20 /* choice of domain shape, see list in global_ljones.c */ -#define CIRCLE_PATTERN 1 /* pattern of circles */ -#define POLYLINE_PATTERN 1 /* pattern of polyline */ +#define CIRCLE_PATTERN 1 /* pattern of circles, see list in global_ljones.c */ -#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ -#define ABSORBING_CORNER_RADIUS 0.0 /* radius of absorbing corners in polygonal line */ +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 100 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ -#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ -#define NMAXPOLY 1000 /* total number of sides of polygonal line */ -#define NCX 30 /* number of circles in x direction */ -#define NCY 20 /* number of circles in y direction */ -#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ -#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.025 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 32 /* number of grid point for grid of disks */ +#define NGRIDY 26 /* number of grid point for grid of disks */ -#define LAMBDA 1.5 /* parameter controlling shape of domain */ -#define MU 0.01 /* second parameter controlling shape of billiard */ -#define FOCI 1 /* set to 1 to draw focal points of ellipse */ -#define NPOLY 4 /* number of sides of polygon */ -#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ -#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ -#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ -#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ -#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ -#define DEBUG 0 /* draw trajectories, for debugging purposes */ +/* Boundary conditions, see list in global_ljones.c */ -/* Simulation parameters */ +#define B_COND 3 -#define NPART 5000 /* number of particles */ -#define NPARTMAX 100000 /* maximal number of particles after resampling */ -#define LMAX 0.01 /* minimal segment length triggering resampling */ -#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ -#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ -#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ -#define SHOWZOOM 1 /* set to 1 to show zoom on specific area */ -#define PRINT_PARTICLE_NUMBER 1 /* set to 1 to print number of particles */ -#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ +/* Parameters for length and speed of simulation */ -#define NSTEPS 1150 /* number of frames of movie */ -#define TIME 3000 /* time between movie frames, for fluidity of real-time simulation */ -#define DPHI 0.000005 /* integration step */ -#define NVID 150 /* number of iterations between images displayed on screen */ - -/* Decreasing TIME accelerates the animation and the movie */ -/* For constant speed of movie, TIME*DPHI should be kept constant */ -/* However, increasing DPHI too much deterioriates quality of simulation */ -/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ -/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ - -/* Colors and other graphical parameters */ - -#define COLOR_PALETTE 10 /* Color palette, see list in global_pdes.c */ - -#define NCOLORS 64 /* number of colors */ -#define COLORSHIFT 0 /* hue of initial color */ -#define RAINBOW_COLOR 1 /* set to 1 to use different colors for all particles */ -#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSTEPS 1300 /* number of frames of movie */ +#define NVID 150 /* number of iterations between images displayed on screen */ #define NSEG 100 /* number of segments of boundary */ -#define LENGTH 0.025 /* length of velocity vectors */ -#define BILLIARD_WIDTH 2 /* width of billiard */ -#define PARTICLE_WIDTH 3 /* width of particles */ -#define FRONT_WIDTH 3 /* width of wave front */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ -#define BLACK 1 /* set to 1 for black background */ -#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ -#define OUTER_COLOR 270.0 /* color outside billiard */ -#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ -#define PAINT_EXT 1 /* set to 1 to paint exterior */ - -#define PAUSE 1000 /* number of frames after which to pause */ +#define PAUSE 1000 /* number of frames after which to pause */ #define PSLEEP 1 /* sleep time during pause */ #define SLEEP1 1 /* initial sleeping time */ -#define SLEEP2 1000 /* final sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + + +/* Plot type, see list in global_ljones.c */ + +#define PLOT 1 + +/* Color schemes */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_ljones.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 1 /* choice of color scheme, see list in global_ljones.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -50.0 /* amplitude of variation of hue for color scheme C_HUE */ + +/* particle properties */ + +#define PARTICLE_HUE_MIN 330.0 /* color of original particle */ +#define PARTICLE_HUE_MAX 30.0 /* color of saturated particle */ +#define PARTICLE_EMAX 2.0e1 /* max energy for particle to survive */ + +#define RANDOM_RADIUS 0 /* set to 1 for random circle radius */ +#define MOVE_PARTICLES 1 /* set to 1 for mobile particles */ +#define INERTIA 1 /* set to 1 for taking inertia into account */ +#define DT_PARTICLE 2.0e-6 /* time step for particle displacement */ +#define KREPEL 50.0 /* constant in repelling force between particles */ +#define EQUILIBRIUM_DIST 4.0 /* Lennard-Jones equilibrium distance */ +#define REPEL_RADIUS 20.0 /* radius in which repelling force acts (in units of particle radius) */ +#define DAMPING 1.5e5 /* damping coefficient of particles */ +#define PARTICLE_MASS 1.0 /* mass of particle of radius MU */ +#define V_INITIAL 5.0 /* initial velocity range */ +#define SIGMA 5.0 /* noise intensity in thermostat */ +#define BETA 2.0e-1 /* initial inverse temperature */ +#define MU_XI 0.1 /* friction constant in thermostat */ +#define KSPRING_BOUNDARY 1.0e5 /* confining harmonic potential outside simulation region */ +#define NBH_DIST_FACTOR 4.5 /* radius in which to count neighbours */ + +#define INCREASE_BETA 0 /* set to 1 to increase BETA during simulation */ +#define BETA_FACTOR 5.0e2 /* factor by which to change BETA during simulation */ + +#define INCREASE_KREPEL 0 /* set to 1 to increase KREPEL during simulation */ +#define KREPEL_FACTOR 1000.0 /* factor by which to change KREPEL during simulation */ + +#define ADD_PARTICLES 1 /* set to 1 to add particles */ +#define ADD_TIME 300 /* time at which to add first particle */ +#define ADD_PERIOD 2000 /* time interval between adding further particles */ + +#define FLOOR_FORCE 1 /* set to 1 to limit force on particle to FMAX */ +#define FMAX 2.0e10 /* maximal force */ + +#define HASHX 32 /* size of hashgrid in x direction */ +#define HASHY 18 /* size of hashgrid in y direction */ +#define HASHMAX 100 /* maximal number of particles per hashgrid cell */ +#define HASHGRID_PADDING 0.1 /* padding of hashgrid outside simulation window */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 1 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ ``` -### 4 November 21 - A rotating hexagonal parabolic resonator ### +### 14 December 21 - 6 out of phase waves in a von Koch snowflake fractal ### -**Program:** `wave_billiard_rotate.c` +**Program:** `wave_billiard.c` -**Initial condition in function `animation()`:** `init_circular_wave(0.0, 0.0, phi, psi, xy_in);` +**Initial condition in function `animation()`:** + +``` + init_circular_wave(0.7, 0.0, phi, psi, xy_in); + sign = 1.0; + for (i=1; i<6; i++) + { + sign = - sign; + add_circular_wave(sign, 0.7*cos((double)(2*i)*PI/6.0), 0.7*sin((double)(2*i)*PI/6.0), phi, psi, xy_in); + } +``` ``` #define MOVIE 1 /* set to 1 to generate movie */ -#define DOUBLE_MOVIE 1 /* set to 1 to produce movies for wave height and energy simultaneously */ +#define DOUBLE_MOVIE 0 /* set to 1 to produce movies for wave height and energy simultaneously */ /* General geometrical parameters */ @@ -1022,37 +2000,36 @@ updated gradually. /* Choice of the billiard table */ -#define B_DOMAIN 32 /* choice of domain shape, see list in global_pdes.c */ +#define B_DOMAIN 41 /* choice of domain shape, see list in global_pdes.c */ -#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ +#define CIRCLE_PATTERN 2 /* pattern of circles or polygons, see list in global_pdes.c */ #define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ #define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 1 /* set to 1 to randomize angle of polygons */ -#define LAMBDA 0.0 /* parameter controlling the dimensions of domain */ +#define LAMBDA 1.2 /* parameter controlling the dimensions of domain */ #define MU 1.0 /* parameter controlling the dimensions of domain */ #define NPOLY 6 /* number of sides of polygon */ -#define APOLY -0.02 /* angle by which to turn polygon, in units of Pi/2 */ -#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define APOLY 0.33333333333333333 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 5 /* depth of computation of Menger gasket */ #define MRATIO 3 /* ratio defining Menger gasket */ #define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ #define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ #define FOCI 1 /* set to 1 to draw focal points of ellipse */ -#define NGRIDX 16 /* number of grid point for grid of disks */ -#define NGRIDY 20 /* number of grid point for grid of disks */ - -#define ROTATION 0.00275 /* rotation angle per frame */ +#define NGRIDX 10 /* number of grid point for grid of disks */ +#define NGRIDY 12 /* number of grid point for grid of disks */ #define X_SHOOTER -0.2 #define Y_SHOOTER -0.6 #define X_TARGET 0.4 #define Y_TARGET 0.7 /* shooter and target positions in laser fight */ -#define ISO_XSHIFT_LEFT -1.65 -#define ISO_XSHIFT_RIGHT 0.4 -#define ISO_YSHIFT_LEFT -0.05 -#define ISO_YSHIFT_RIGHT -0.05 -#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ /* You can add more billiard tables by adapting the functions */ /* xy_in_billiard and draw_billiard below */ @@ -1066,9 +2043,9 @@ updated gradually. #define OMEGA 0.002 /* frequency of periodic excitation */ #define AMPLITUDE 1.0 /* amplitude of periodic excitation */ #define COURANT 0.02 /* Courant number */ -#define COURANTB 0.02 /* Courant number in medium B */ +#define COURANTB 0.01 /* Courant number in medium B */ #define GAMMA 0.0 /* damping factor in wave equation */ -#define GAMMAB 5.0e-3 /* damping factor in wave equation */ +#define GAMMAB 1.0e-6 /* damping factor in wave equation */ #define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ #define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ #define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ @@ -1081,12 +2058,12 @@ updated gradually. /* Boundary conditions, see list in global_pdes.c */ -#define B_COND 2 +#define B_COND 3 /* Parameters for length and speed of simulation */ -#define NSTEPS 4350 /* number of frames of movie */ -#define NVID 50 /* number of iterations between images displayed on screen */ +#define NSTEPS 4500 /* number of frames of movie */ +#define NVID 35 /* number of iterations between images displayed on screen */ #define NSEG 100 /* number of segments of boundary */ #define INITIAL_TIME 0 /* time after which to start saving frames */ #define BOUNDARY_WIDTH 2 /* width of billiard boundary */ @@ -1096,32 +2073,33 @@ updated gradually. #define SLEEP1 1 /* initial sleeping time */ #define SLEEP2 1 /* final sleeping time */ #define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ -#define END_FRAMES 100 /* number of still frames at end of movie */ +#define END_FRAMES 50 /* number of still frames at end of movie */ /* Parameters of initial condition */ #define INITIAL_AMP 0.75 /* amplitude of initial condition */ -#define INITIAL_VARIANCE 0.00025 /* variance of initial condition */ -#define INITIAL_WAVELENGTH 0.02 /* wavelength of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ /* Plot type, see list in global_pdes.c */ -#define PLOT 1 +#define PLOT 0 -#define PLOT_B 0 /* plot type for second movie */ +#define PLOT_B 4 /* plot type for second movie */ /* Color schemes */ -#define COLOR_PALETTE 10 /* Color palette, see list in global_pdes.c */ +#define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ #define BLACK 1 /* background */ #define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ #define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ -#define SLOPE 0.2 /* sensitivity of color on wave amplitude */ +#define SLOPE 0.25 /* sensitivity of color on wave amplitude */ #define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ -#define E_SCALE 50.0 /* scaling factor for energy representation */ +#define E_SCALE 100.0 /* scaling factor for energy representation */ +#define LOG_SCALE 2.0 /* scaling factor for energy log representation */ #define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ #define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ @@ -1131,7 +2109,9 @@ updated gradually. #define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ #define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ -#define COLORBAR_RANGE 7.5 /* scale of color scheme bar */ +#define COLORBAR_RANGE 10.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 3.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ #define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ @@ -1141,23 +2121,15 @@ updated gradually. ``` -### 3 November 21 - Trajectories in a triangular billiard ### +### 13 December 21 - Spreading of an epidemic: A spatial SIR model ### -**Program:** `particle_trajectory.c` - -**Initial condition in function `animation()`:** -``` - alpha = PI*1.25; - x = -1.0 + 0.5*cos(DPI*time + alpha); - y = LAMBDA - 2.0 + 0.5*sin(DPI*time + alpha); - alpha = PI/3.0; - compute_trajectories_xy(x, y, alpha, DPI + alpha, configs, trajectory, traj_length); - -``` +**Program:** `sir.c` (variant of `lennardjones.c`) ``` #define MOVIE 1 /* set to 1 to generate movie */ +/* General geometrical parameters */ + #define WINWIDTH 1280 /* window width */ #define WINHEIGHT 720 /* window height */ @@ -1166,88 +2138,139 @@ updated gradually. #define YMIN -1.125 #define YMAX 1.125 /* y interval for 9/16 aspect ratio */ -#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ +/* Choice of the billiard table */ -/* Choice of the billiard table, see global_particles.c */ +#define CIRCLE_PATTERN 8 /* pattern of circles, see list in global_ljones.c */ -#define B_DOMAIN 5 /* choice of domain shape */ +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define PDISC_DISTANCE 5.0 /* minimal distance in Poisson disc process */ +#define PDISC_CANDIDATES 100 /* number of candidates in construction of Poisson disc process */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ -#define CIRCLE_PATTERN 5 /* pattern of circles */ -#define POLYLINE_PATTERN 1 /* pattern of polyline */ +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.025 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 32 /* number of grid point for grid of disks */ +#define NGRIDY 26 /* number of grid point for grid of disks */ -#define ABSORBING_CIRCLES 0 /* set to 1 for circular scatterers to be absorbing */ +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ -#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ -#define NMAXPOLY 1000 /* total number of sides of polygonal line */ -#define NCX 9 /* number of circles in x direction */ -#define NCY 20 /* number of circles in y direction */ -#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ -#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ +/* Boundary conditions, see list in global_ljones.c */ -#define LAMBDA 1.732050808 /* sqrt(3) - parameter controlling shape of domain */ -#define MU 0.04 /* second parameter controlling shape of billiard */ -#define FOCI 1 /* set to 1 to draw focal points of ellipse */ -#define NPOLY 4 /* number of sides of polygon */ -#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ -#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ -#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ -#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ +#define B_COND 3 -#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ -#define DEBUG 0 /* draw trajectories, for debugging purposes */ +/* Parameters for length and speed of simulation */ -/* Simulation parameters */ - -#define NPART 24 /* number of particles */ -#define NPARTMAX 100000 /* maximal number of particles after resampling */ -#define TRAJ_LENGTH 48 /* length of trajectory */ -#define LMAX 0.01 /* minimal segment length triggering resampling */ -#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ -#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ -#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ -#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ - -#define NSTEPS 3000 /* number of frames of movie */ -#define TIME 2500 /* time between movie frames, for fluidity of real-time simulation */ -#define DPHI 0.00001 /* integration step */ -#define NVID 150 /* number of iterations between images displayed on screen */ - -/* Decreasing TIME accelerates the animation and the movie */ -/* For constant speed of movie, TIME*DPHI should be kept constant */ -/* However, increasing DPHI too much deterioriates quality of simulation */ -/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ -/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ - -/* Colors and other graphical parameters */ - -#define COLOR_PALETTE 14 /* Color palette, see list in global_pdes.c */ - -#define NCOLORS 64 /* number of colors */ -#define COLORSHIFT 0 /* hue of initial color */ -#define RAINBOW_COLOR 1 /* set to 1 to use different colors for all particles */ -#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSTEPS 3500 /* number of frames of movie */ +#define NVID 150 /* number of iterations between images displayed on screen */ #define NSEG 100 /* number of segments of boundary */ -#define LENGTH 0.03 /* length of velocity vectors */ -#define BILLIARD_WIDTH 2 /* width of billiard */ -#define PARTICLE_WIDTH 2 /* width of particles */ -#define FRONT_WIDTH 3 /* width of wave front */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ -#define BLACK 1 /* set to 1 for black background */ -#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ -#define OUTER_COLOR 270.0 /* color outside billiard */ -#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ -#define PAINT_EXT 1 /* set to 1 to paint exterior */ - -#define PAUSE 1000 /* number of frames after which to pause */ +#define PAUSE 1000 /* number of frames after which to pause */ #define PSLEEP 1 /* sleep time during pause */ #define SLEEP1 1 /* initial sleeping time */ -#define SLEEP2 1000 /* final sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + + +/* Plot type, see list in global_ljones.c */ + +#define PLOT 2 + +/* Color schemes */ + +#define COLOR_PALETTE 0 /* Color palette, see list in global_ljones.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 1 /* choice of color scheme, see list in global_ljones.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -50.0 /* amplitude of variation of hue for color scheme C_HUE */ + +/* particle properties */ + +#define PARTICLE_HUE_MIN 330.0 /* color of original particle */ +#define PARTICLE_HUE_MAX 30.0 /* color of saturated particle */ +#define PARTICLE_EMAX 5.0e1 /* max energy for particle to survive */ + +#define RANDOM_RADIUS 0 /* set to 1 for random circle radius */ +#define MOVE_PARTICLES 1 /* set to 1 for mobile particles */ +#define INERTIA 1 /* set to 1 for taking inertia into account */ +#define DT_PARTICLE 2.0e-6 /* time step for particle displacement */ +#define KREPEL 100.0 /* constant in repelling force between particles */ +#define EQUILIBRIUM_DIST 3.0 /* Lennard-Jones equilibrium distance */ +#define REPEL_RADIUS 20.0 /* radius in which repelling force acts (in units of particle radius) */ +#define DAMPING 1.5e5 /* damping coefficient of particles */ +#define PARTICLE_MASS 1.0 /* mass of particle of radius MU */ +#define V_INITIAL 10.0 /* initial velocity range */ +#define SIGMA 10.0 /* noise intensity in thermostat */ +#define BETA 3.0e-3 /* initial inverse temperature */ +#define MU_XI 0.1 /* friction constant in thermostat */ +#define KSPRING_BOUNDARY 1.0e6 /* confining harmonic potential outside simulation region */ +#define NBH_DIST_FACTOR 4.5 /* radius in which to count neighbours */ + +#define INCREASE_BETA 0 /* set to 1 to increase BETA during simulation */ +#define BETA_FACTOR 5.0e2 /* factor by which to change BETA during simulation */ + +#define INCREASE_KREPEL 0 /* set to 1 to increase KREPEL during simulation */ +#define KREPEL_FACTOR 1000.0 /* factor by which to change KREPEL during simulation */ + +#define ADD_PARTICLES 0 /* set to 1 to add particles */ +#define ADD_TIME 300 /* time at which to add first particle */ +#define ADD_PERIOD 2000 /* time interval between adding further particles */ + +#define FLOOR_FORCE 0 /* set to 1 to limit force on particle to FMAX */ +#define FMAX 2.0e10 /* maximal force */ + +#define P_PROTECTED 0.5 /* probability of being protected */ +#define CONTAMINATION_RADIUS 2.8 /* radius in which people can contiminate others */ +#define P_INFECTION 0.1 /* probability of getting infected */ +#define P_INFECTION_PROTECTED 0.01 /* probability of getting infected if protected */ +#define INFECTION_CHANGE 0.2 /* time change of infection */ +#define RECOVER_THRESHOLD 100.0 /* threshold for getting recovered */ + +#define HASHX 16 /* size of hashgrid in x direction */ +#define HASHY 9 /* size of hashgrid in y direction */ +#define HASHMAX 100 /* maximal number of particles per hashgrid cell */ +#define HASHGRID_PADDING 0.1 /* padding of hashgrid outside simulation window */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 1 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ ``` -### 2 November 21 - Classics revisited: circular wave starting from the center of an ellipse ### -**Program:** `wave_billiard.c` +### 12 December 21 - Advent, advent... Average energy in a von Koch snowflake (log scale) ### + +**Program:** `wave_billiard_vonKoch.c` (variant of `wave_billiard.c`) **Initial condition in function `animation()`:** `init_circular_wave(0.0, 0.0, phi, psi, xy_in);` @@ -1272,24 +2295,26 @@ updated gradually. /* Choice of the billiard table */ -#define B_DOMAIN 1 /* choice of domain shape, see list in global_pdes.c */ +#define B_DOMAIN 41 /* choice of domain shape, see list in global_pdes.c */ -#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ +#define CIRCLE_PATTERN 2 /* pattern of circles or polygons, see list in global_pdes.c */ #define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ #define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 1 /* set to 1 to randomize angle of polygons */ -#define LAMBDA 1.5 /* parameter controlling the dimensions of domain */ -#define MU 0.5 /* parameter controlling the dimensions of domain */ -#define NPOLY 4 /* number of sides of polygon */ -#define APOLY 0.5 /* angle by which to turn polygon, in units of Pi/2 */ -#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define LAMBDA 1.2 /* parameter controlling the dimensions of domain */ +#define MU 1.0 /* parameter controlling the dimensions of domain */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.3333333333333333 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 5 /* depth of computation of Menger gasket */ +#define MAXDEPTH 5 /* max depth of computation of Menger gasket */ #define MRATIO 3 /* ratio defining Menger gasket */ #define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ #define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ #define FOCI 1 /* set to 1 to draw focal points of ellipse */ -#define NGRIDX 16 /* number of grid point for grid of disks */ -#define NGRIDY 20 /* number of grid point for grid of disks */ +#define NGRIDX 10 /* number of grid point for grid of disks */ +#define NGRIDY 12 /* number of grid point for grid of disks */ #define X_SHOOTER -0.2 #define Y_SHOOTER -0.6 @@ -1314,9 +2339,9 @@ updated gradually. #define OMEGA 0.002 /* frequency of periodic excitation */ #define AMPLITUDE 1.0 /* amplitude of periodic excitation */ #define COURANT 0.02 /* Courant number */ -#define COURANTB 0.02 /* Courant number in medium B */ +#define COURANTB 0.01 /* Courant number in medium B */ #define GAMMA 0.0 /* damping factor in wave equation */ -#define GAMMAB 5.0e-3 /* damping factor in wave equation */ +#define GAMMAB 1.0e-6 /* damping factor in wave equation */ #define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ #define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ #define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ @@ -1333,8 +2358,8 @@ updated gradually. /* Parameters for length and speed of simulation */ -#define NSTEPS 4600 /* number of frames of movie */ -#define NVID 50 /* number of iterations between images displayed on screen */ +#define NSTEPS 1070 /* number of frames of movie */ +#define NVID 40 /* number of iterations between images displayed on screen */ #define NSEG 100 /* number of segments of boundary */ #define INITIAL_TIME 0 /* time after which to start saving frames */ #define BOUNDARY_WIDTH 2 /* width of billiard boundary */ @@ -1344,19 +2369,19 @@ updated gradually. #define SLEEP1 1 /* initial sleeping time */ #define SLEEP2 1 /* final sleeping time */ #define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ -#define END_FRAMES 100 /* number of still frames at end of movie */ +#define END_FRAMES 25 /* number of still frames at end of movie */ /* Parameters of initial condition */ #define INITIAL_AMP 0.75 /* amplitude of initial condition */ #define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ -#define INITIAL_WAVELENGTH 0.02 /* wavelength of initial condition */ +#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ /* Plot type, see list in global_pdes.c */ -#define PLOT 1 +#define PLOT 5 -#define PLOT_B 1 /* plot type for second movie */ +#define PLOT_B 0 /* plot type for second movie */ /* Color schemes */ @@ -1367,9 +2392,10 @@ updated gradually. #define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ #define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ -#define SLOPE 0.35 /* sensitivity of color on wave amplitude */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ #define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ -#define E_SCALE 100.0 /* scaling factor for energy representation */ +#define E_SCALE 150.0 /* scaling factor for energy representation */ +#define LOG_SCALE 1.0 /* scaling factor for energy log representation */ #define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ #define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ @@ -1378,7 +2404,10 @@ updated gradually. #define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ #define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ -#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 6.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ #define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ @@ -1388,17 +2417,622 @@ updated gradually. ``` +### 11 December 21 - Temperature cycling: Lennard-Jones interacting particles with oscillating temperature ### -### 1 November 21 - Particles in a four-sided eccentric parabolic resonator ### +**Program:** `lennardjones.c` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 640 /* number of grid points on x axis */ +#define NY 360 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 20 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 8 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 100 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.03 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 15 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -1.65 +#define ISO_XSHIFT_RIGHT 0.4 +#define ISO_YSHIFT_LEFT -0.05 +#define ISO_YSHIFT_RIGHT -0.05 +#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 1 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 1 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ +#define X_SHIFT -0.9 /* x range on which to apply OSCILLATE_TOPBOT */ + +#define OMEGA 0.00133333333 /* frequency of periodic excitation */ +#define K_BC 3.0 /* spatial period of periodic excitation in y direction */ +#define KX_BC 10.0 /* spatial period of periodic excitation in x direction */ +#define KY_BC 3.3333 /* spatial period of periodic excitation in y direction */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.015 /* Courant number in medium B */ +#define GAMMA 3.0e-6 /* damping factor in wave equation */ +#define GAMMAB 5.0e-4 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-6 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPAB 1.0e-6 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 5500 /* number of frames of movie */ +#define NVID 150 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.2 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.002 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.1 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 0 + +/* Color schemes */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 1 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 2500.0 /* scaling factor for energy representation */ +#define LOG_SCALE 2.0 /* scaling factor for energy log representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -50.0 /* amplitude of variation of hue for color scheme C_HUE */ + +/* particle properties */ + +#define PARTICLE_HUE_MIN 330.0 /* color of original particle */ +#define PARTICLE_HUE_MAX 30.0 /* color of saturated particle */ +#define PARTICLE_EMAX 2.0e1 /* max energy for particle to survive */ + +#define RANDOM_RADIUS 0 /* set to 1 for random circle radius */ +#define MOVE_PARTICLES 1 /* set to 1 for mobile particles */ +#define INERTIA 1 /* set to 1 for taking inertia into account */ +#define DT_PARTICLE 2.0e-6 /* time step for particle displacement */ +#define KREPEL 50.0 /* constant in repelling force between particles */ +#define EQUILIBRIUM_DIST 4.0 /* Lennard-Jones equilibrium distance */ +#define REPEL_RADIUS 20.0 /* radius in which repelling force acts (in units of particle radius) */ +#define DAMPING 1.5e5 /* damping coefficient of particles */ +#define PARTICLE_MASS 1.0 /* mass of particle of radius MU */ +#define V_INITIAL 5.0 /* initial velocity range */ +#define SIGMA 5.0 /* noise intensity in thermostat */ +#define BETA 2.0e-3 /* initial inverse temperature */ +#define MU_XI 0.1 /* friction constant in thermostat */ +#define KSPRING_BOUNDARY 1.0e5 /* confining harmonic potential outside simulation region */ + +#define INCREASE_BETA 1 /* set to 1 to increase BETA during simulation */ +#define BETA_FACTOR 1.0e3 /* factor by which to change BETA during simulation */ + +#define INCREASE_KREPEL 0 /* set to 1 to increase KREPEL during simulation */ +#define KREPEL_FACTOR 1000.0 /* factor by which to change KREPEL during simulation */ + +#define FLOOR_FORCE 0 /* set to 1 to limit force on particle to FMAX */ +#define FMAX 2.0e18 /* maximal force */ + +#define HASHX 32 /* size of hashgrid in x direction */ +#define HASHY 18 /* size of hashgrid in y direction */ +#define HASHMAX 100 /* maximal number of particles per hashgrid cell */ +#define HASHGRID_PADDING 0.1 /* padding of hashgrid outside simulation window */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 1 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 10 December 21 - A polygonal unilluminable room without right angles ### **Program:** `particle_billiard.c` +**Initial condition in function `animation()`:** `init_drop_config(x_shooter, y_shooter, 0.0, 0.0 + DPI, configs);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 30 /* choice of domain shape */ + +#define CIRCLE_PATTERN 1 /* pattern of circles */ +#define POLYLINE_PATTERN 6 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 100000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 100000 /* total number of sides of polygonal line */ +#define NCX 30 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ +#define SDEPTH 1 /* Sierpinski gastket depth */ + +#define LAMBDA 0.8 /* parameter controlling shape of domain */ +#define MU 0.007 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 10000 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 1 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 1 /* set to 1 to show zoom on specific area */ +#define PRINT_PARTICLE_NUMBER 1 /* set to 1 to print number of particles */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 2500 /* number of frames of movie */ +#define TIME 1500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.00001 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 11 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 16 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 1 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.015 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 2 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 1 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ + +``` + +### 9 December 21 - Crystal formation in a Lennard-Jones interacting particle system with a thermostat ### + +**Program:** `lennardjones.c` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 640 /* number of grid points on x axis */ +#define NY 360 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 20 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 8 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 100 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.03 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 15 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -1.65 +#define ISO_XSHIFT_RIGHT 0.4 +#define ISO_YSHIFT_LEFT -0.05 +#define ISO_YSHIFT_RIGHT -0.05 +#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 1 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 1 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ +#define X_SHIFT -0.9 /* x range on which to apply OSCILLATE_TOPBOT */ + +#define OMEGA 0.00133333333 /* frequency of periodic excitation */ +#define K_BC 3.0 /* spatial period of periodic excitation in y direction */ +#define KX_BC 10.0 /* spatial period of periodic excitation in x direction */ +#define KY_BC 3.3333 /* spatial period of periodic excitation in y direction */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.015 /* Courant number in medium B */ +#define GAMMA 3.0e-6 /* damping factor in wave equation */ +#define GAMMAB 5.0e-4 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-6 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPAB 1.0e-6 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 4000 /* number of frames of movie */ +#define NVID 150 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.2 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.002 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.1 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 0 + +/* Color schemes */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 1 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 2500.0 /* scaling factor for energy representation */ +#define LOG_SCALE 2.0 /* scaling factor for energy log representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -50.0 /* amplitude of variation of hue for color scheme C_HUE */ + +/* particle properties */ + +#define PARTICLE_HUE_MIN 330.0 /* color of original particle */ +#define PARTICLE_HUE_MAX 30.0 /* color of saturated particle */ +#define PARTICLE_EMAX 1.0e2 /* max energy for particle to survive */ + +#define RANDOM_RADIUS 0 /* set to 1 for random circle radius */ +#define MOVE_PARTICLES 1 /* set to 1 for mobile particles */ +#define INERTIA 1 /* set to 1 for taking inertia into account */ +#define DT_PARTICLE 2.0e-6 /* time step for particle displacement */ +#define KREPEL 50.0 /* constant in repelling force between particles */ +#define EQUILIBRIUM_DIST 4.0 /* Lennard-Jones equilibrium distance */ +#define REPEL_RADIUS 20.0 /* radius in which repelling force acts (in units of particle radius) */ +#define DAMPING 1.5e5 /* damping coefficient of particles */ +#define PARTICLE_MASS 1.0 /* mass of particle of radius MU */ +#define V_INITIAL 5.0 /* initial velocity range */ +#define SIGMA 5.0 /* noise intensity in thermostat */ +#define BETA 1.0e-3 /* initial inverse temperature */ +#define MU_XI 0.1 /* friction constant in thermostat */ +#define KSPRING_BOUNDARY 1.0e5 /* confining harmonic potential outside simulation region */ + +#define INCREASE_BETA 1 /* set to 1 to increase BETA during simulation */ +#define BETA_FACTOR 1.0e5 /* factor by which to change BETA during simulation */ + +#define INCREASE_KREPEL 0 /* set to 1 to increase KREPEL during simulation */ +#define KREPEL_FACTOR 1000.0 /* factor by which to change KREPEL during simulation */ + +#define FLOOR_FORCE 0 /* set to 1 to limit force on particle to FMAX */ +#define FMAX 2.0e18 /* maximal force */ + +#define HASHX 32 /* size of hashgrid in x direction */ +#define HASHY 18 /* size of hashgrid in y direction */ +#define HASHMAX 100 /* maximal number of particles per hashgrid cell */ +#define HASHGRID_PADDING 0.1 /* padding of hashgrid outside simulation window */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 1 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 8 December 21 - Heavily peated: wave starting off center in a von Koch snowflake, average energy on log scale ### + +**Program:** `wave_billiard.c` + +**Initial condition in function `animation()`:** `init_circular_wave(0.6*cos(PI/6.0), 0.6*sin(PI/6.0), phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 1 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 41 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 2 /* pattern of circles or polygons, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 1 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 1.0 /* parameter controlling the dimensions of domain */ +#define MU 1.0 /* parameter controlling the dimensions of domain */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 2.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 5 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 10 /* number of grid point for grid of disks */ +#define NGRIDY 12 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.01 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 1.0e-6 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 2500 /* number of frames of movie */ +#define NVID 40 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 50 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 5 + +#define PLOT_B 4 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 13 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 100.0 /* scaling factor for energy representation */ +#define LOG_SCALE 2.0 /* scaling factor for energy log representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 3.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 3.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 7 December 21 - A lighthouse beam in a mirrored heptagon ### + +**Program:** `particle_trajectory.c` + **Initial condition in function `animation()`:** ``` - init_partial_drop_config(LAMBDA, 0.0, 0.0, DPI, 0, NPART/4, 0, configs, color, newcolor); - init_partial_drop_config(-LAMBDA, 0.0, 0.0, DPI, NPART/4, NPART/2, 0, configs, color, newcolor); - init_partial_drop_config(0.0, LAMBDA, 0.0, DPI, NPART/2, 3*NPART/4, 0, configs, color, newcolor); - init_partial_drop_config(0.0, -LAMBDA, 0.0, DPI, 3*NPART/4, NPART, 0, configs, color, newcolor); + time = (double)i/(double)(NSTEPS-1); + x = 0.0; + y = 0.0; + alpha = (DPI/(double)NPOLY)*time; ``` ``` @@ -1416,22 +3050,25 @@ updated gradually. /* Choice of the billiard table, see global_particles.c */ -#define B_DOMAIN 15 /* choice of domain shape */ +#define B_DOMAIN 30 /* choice of domain shape */ -#define CIRCLE_PATTERN 2 /* pattern of circles */ +#define CIRCLE_PATTERN 5 /* pattern of circles */ +#define POLYLINE_PATTERN 5 /* pattern of polyline */ -#define ABSORBING_CIRCLES 0 /* set to 1 for circular scatterers to be absorbing */ +#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ -#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ -#define NCX 30 /* number of circles in x direction */ +#define NMAXCIRCLES 10000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 10000 /* total number of sides of polygonal line */ +#define NCX 9 /* number of circles in x direction */ #define NCY 20 /* number of circles in y direction */ #define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ #define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ +#define SDEPTH 4 /* Sierpinski gastket depth */ -#define LAMBDA 0.3 /* parameter controlling shape of domain */ -#define MU 0.7 /* second parameter controlling shape of billiard */ +#define LAMBDA 1.0 /* parameter controlling shape of domain */ +#define MU 0.005 /* second parameter controlling shape of billiard */ #define FOCI 1 /* set to 1 to draw focal points of ellipse */ -#define NPOLY 4 /* number of sides of polygon */ +#define NPOLY 7 /* number of sides of polygon */ #define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ #define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ #define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ @@ -1442,17 +3079,20 @@ updated gradually. /* Simulation parameters */ -#define NPART 10000 /* number of particles */ +#define NPART 1 /* number of particles */ #define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define TRAJ_LENGTH 128 /* length of trajectory */ #define LMAX 0.01 /* minimal segment length triggering resampling */ #define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ #define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ #define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 0 /* set to 1 to show zoom on specific area */ #define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ +#define PRINT_TRAJECTORY_LENGTH 0 /* set to 1 to print length of trajectory 0 */ -#define NSTEPS 4600 /* number of frames of movie */ +#define NSTEPS 4000 /* number of frames of movie */ #define TIME 2500 /* time between movie frames, for fluidity of real-time simulation */ -#define DPHI 0.0000025 /* integration step */ +#define DPHI 0.00001 /* integration step */ #define NVID 150 /* number of iterations between images displayed on screen */ /* Decreasing TIME accelerates the animation and the movie */ @@ -1463,16 +3103,443 @@ updated gradually. /* Colors and other graphical parameters */ -#define COLOR_PALETTE 1 /* Color palette, see list in global_pdes.c */ +#define COLOR_PALETTE 14 /* Color palette, see list in global_pdes.c */ #define NCOLORS 64 /* number of colors */ #define COLORSHIFT 0 /* hue of initial color */ #define RAINBOW_COLOR 0 /* set to 1 to use different colors for all particles */ #define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ #define NSEG 100 /* number of segments of boundary */ -#define LENGTH 0.02 /* length of velocity vectors */ +#define LENGTH 0.03 /* length of velocity vectors */ #define BILLIARD_WIDTH 2 /* width of billiard */ -#define PARTICLE_WIDTH 1 /* width of particles */ +#define PARTICLE_WIDTH 2 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 1 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ +#define END_FRAMES 100 /* number of frames at end of movie */ + +``` + +### 6 December 21 - A crude model of seismic waves ### + +**Program:** `wave_diffraction.c` (variant of `wave_billiard.c`) + +**Initial condition in function `animation()`:** `init_circular_wave(0.0, 0.98, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 0 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 2560 /* number of grid points on x axis */ +#define NY 1440 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 1 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 2 /* pattern of circles or polygons, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 1 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 1.0 /* parameter controlling the dimensions of domain */ +#define MU 0.03 /* parameter controlling the dimensions of domain */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 2.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 5 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 10 /* number of grid point for grid of disks */ +#define NGRIDY 12 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.01 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 1.0e-6 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 2800 /* number of frames of movie */ +#define NVID 50 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 50 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0001 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.01 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 1 + +#define PLOT_B 0 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 15 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 2.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 100.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 1.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 5 December 21 - Grain boundary dynamics in a particle system with Lennard-Jones interaction of increasing strength ### + +**Program:** `lennardjones.c` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 640 /* number of grid points on x axis */ +#define NY 360 Crack dynamics in a particle system with Lennard-Jones interaction of increasing constant /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 20 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 8 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 100 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.02 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 15 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -1.65 +#define ISO_XSHIFT_RIGHT 0.4 +#define ISO_YSHIFT_LEFT -0.05 +#define ISO_YSHIFT_RIGHT -0.05 +#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 1 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 1 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ +#define X_SHIFT -0.9 /* x range on which to apply OSCILLATE_TOPBOT */ + +#define OMEGA 0.00133333333 /* frequency of periodic excitation */ +#define K_BC 3.0 /* spatial period of periodic excitation in y direction */ +#define KX_BC 10.0 /* spatial period of periodic excitation in x direction */ +#define KY_BC 3.3333 /* spatial period of periodic excitation in y direction */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.015 /* Courant number in medium B */ +#define GAMMA 3.0e-6 /* damping factor in wave equation */ +#define GAMMAB 5.0e-4 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-6 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPAB 1.0e-6 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 3000 /* number of frames of movie */ +#define NVID 150 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.2 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.002 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.1 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 0 + +/* Color schemes */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 1 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 2500.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -50.0 /* amplitude of variation of hue for color scheme C_HUE */ + +/* particle properties */ + +#define PARTICLE_HUE_MIN 330.0 /* color of original particle */ +#define PARTICLE_HUE_MAX 30.0 /* color of saturated particle */ +#define PARTICLE_EMAX 2.5e9 /* max energy for particle to survive */ + +#define RANDOM_RADIUS 0 /* set to 1 for random circle radius */ +#define MOVE_PARTICLES 1 /* set to 1 for mobile particles */ +#define INERTIA 1 /* set to 1 for taking inertia into account */ +#define DT_PARTICLE 2.0e-10 /* time step for particle displacement */ +#define KREPEL 50.0 /* constant in repelling force between particles */ +#define EQUILIBRIUM_DIST 15.0 /* Lennard-Jones equilibrium distance */ +#define REPEL_RADIUS 20.0 /* radius in which repelling force acts (in units of particle radius) */ +#define DAMPING 1.5e5 /* damping coefficient of particles */ +#define PARTICLE_MASS 1.0 /* mass of particle of radius MU */ +#define V_INITIAL 5.0e5 /* initial velocity range */ + +#define INCREASE_KREPEL 1 /* set to 1 to increase KREPEL during simulation */ +#define KREPEL_FACTOR 1000.0 /* factor by which to change KREPEL during simulation */ + +#define FLOOR_FORCE 0 /* set to 1 to limit force on particle to FMAX */ +#define FMAX 2.0e18 /* maximal force */ + +#define HASHX 32 /* size of hashgrid in x direction */ +#define HASHY 18 /* size of hashgrid in y direction */ +#define HASHMAX 100 /* maximal number of particles per hashgrid cell */ +#define HASHGRID_PADDING 0.1 /* padding of hashgrid outside simulation window */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 1 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 4 December 21 - A lighthouse beam in a Tokarsky room ### + +**Program:** `particle_trajectory.c` + +**Initial condition in function `animation()`:** + +``` + time = (double)i/(double)(NSTEPS-1); + x = - 0.95; + y = 0.0; + alpha = PID*(0.5 + time); + compute_trajectories_xy(x, y, alpha, alpha + DPI, configs, trajectory, traj_length); +``` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 30 /* choice of domain shape */ + +#define CIRCLE_PATTERN 5 /* pattern of circles */ +#define POLYLINE_PATTERN 1 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 10000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 10000 /* total number of sides of polygonal line */ +#define NCX 9 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ +#define SDEPTH 4 /* Sierpinski gastket depth */ + +#define LAMBDA 1.0 /* parameter controlling shape of domain */ +#define MU 0.005 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 1 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define TRAJ_LENGTH 256 /* length of trajectory */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 1 /* set to 1 to show zoom on specific area */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ +#define PRINT_TRAJECTORY_LENGTH 1 /* set to 1 to print length of trajectory 0 */ + +#define NSTEPS 13300 /* number of frames of movie */ +#define TIME 2500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.00001 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 11 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 32 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 0 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.03 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 2 /* width of particles */ #define FRONT_WIDTH 3 /* width of wave front */ #define BLACK 1 /* set to 1 for black background */ @@ -1487,3 +3554,488 @@ updated gradually. #define SLEEP2 1000 /* final sleeping time */ ``` + +### 3 December 21 - Crystalline defect propagation in a system of particles with Lennard-Jones interaction ### + +**Program:** `lennardjones.c` + +``` +#define MOVIE 0 /* set to 1 to generate movie */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 640 /* number of grid points on x axis */ +#define NY 360 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 20 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 8 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 100 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.02 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 15 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -1.65 +#define ISO_XSHIFT_RIGHT 0.4 +#define ISO_YSHIFT_LEFT -0.05 +#define ISO_YSHIFT_RIGHT -0.05 +#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 1 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 1 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ +#define X_SHIFT -0.9 /* x range on which to apply OSCILLATE_TOPBOT */ + +#define OMEGA 0.00133333333 /* frequency of periodic excitation */ +#define K_BC 3.0 /* spatial period of periodic excitation in y direction */ +#define KX_BC 10.0 /* spatial period of periodic excitation in x direction */ +#define KY_BC 3.3333 /* spatial period of periodic excitation in y direction */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.015 /* Courant number in medium B */ +#define GAMMA 3.0e-6 /* damping factor in wave equation */ +#define GAMMAB 5.0e-4 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-6 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPAB 1.0e-6 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 2000 /* number of frames of movie */ +#define NVID 150 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.2 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.002 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.1 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 0 + +/* Color schemes */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 1 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 2500.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -50.0 /* amplitude of variation of hue for color scheme C_HUE */ + +/* particle properties */ + +#define PARTICLE_HUE_MIN 330.0 /* color of original particle */ +#define PARTICLE_HUE_MAX 30.0 /* color of saturated particle */ +#define PARTICLE_EMAX 1.0e9 /* max energy for particle to survive */ + +#define RANDOM_RADIUS 0 /* set to 1 for random circle radius */ +#define MOVE_PARTICLES 1 /* set to 1 for mobile particles */ +#define INERTIA 1 /* set to 1 for taking inertia into account */ +#define DT_PARTICLE 2.0e-10 /* time step for particle displacement */ +#define KREPEL 2.5e3 /* constant in repelling force between particles */ +#define EQUILIBRIUM_DIST 15.0 /* Lennard-Jones equilibrium distance */ +#define REPEL_RADIUS 20.0 /* radius in which repelling force acts (in units of particle radius) */ +#define DAMPING 2.5e5 /* damping coefficient of particles */ +#define PARTICLE_MASS 1.0 /* mass of particle of radius MU */ +#define V_INITIAL 0.0e2 /* initial velocity range */ + +#define FLOOR_FORCE 0 /* set to 1 to limit force on particle to FMAX */ +#define FMAX 2.0e18 /* maximal force */ + +#define HASHX 32 /* size of hashgrid in x direction */ +#define HASHY 18 /* size of hashgrid in y direction */ +#define HASHMAX 100 /* maximal number of particles per hashgrid cell */ +#define HASHGRID_PADDING 0.1 /* padding of hashgrid outside simulation window */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 1 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 2 December 21 - Wave protection comparison 10: Triangles pointing right vs triangles pointing left ### + +**Program:** `wave_comparison.c` + +**Initial condition in function `animation()`:** `int_planar_wave_comp(XMIN + 0.015, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 40 /* choice of domain shape, see list in global_pdes.c */ +#define B_DOMAIN_B 40 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 0 /* pattern of circles, see list in global_pdes.c */ +#define CIRCLE_PATTERN_B 0 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 0.8 /* parameter controlling the dimensions of domain */ +#define MU 0.04665361 /* parameter controlling the dimensions of domain */ +#define MUB 0.04665361 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 2.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define APOLY_B 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 20 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -1.65 +#define ISO_XSHIFT_RIGHT 0.4 +#define ISO_YSHIFT_LEFT -0.05 +#define ISO_YSHIFT_RIGHT -0.05 +#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.0 /* frequency of periodic excitation */ +#define AMPLITUDE 0.025 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.004 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 1.0e-8 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-6 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 3750 /* number of frames of movie */ +#define NVID 25 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 150 /* time after which to start saving frames */ +#define COMPUTE_ENERGIES 1 /* set to 1 to compute and print energies */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.02 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 1 + +/* Color schemes */ + +#define COLOR_PALETTE 13 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.5 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 2000.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -220.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 60.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 5.0 /* max value of wave amplitude */ + +``` + +### 1 December 21 - Crystal formation: particles interacting with a Lennard-Jones potential ### + +**Program:** `lennardjones.c` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 640 /* number of grid points on x axis */ +#define NY 360 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 20 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 8 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 340 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.04 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 15 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -1.65 +#define ISO_XSHIFT_RIGHT 0.4 +#define ISO_YSHIFT_LEFT -0.05 +#define ISO_YSHIFT_RIGHT -0.05 +#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 1 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 1 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ +#define X_SHIFT -0.9 /* x range on which to apply OSCILLATE_TOPBOT */ + +#define OMEGA 0.00133333333 /* frequency of periodic excitation */ +#define K_BC 3.0 /* spatial period of periodic excitation in y direction */ +#define KX_BC 10.0 /* spatial period of periodic excitation in x direction */ +#define KY_BC 3.3333 /* spatial period of periodic excitation in y direction */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.015 /* Courant number in medium B */ +#define GAMMA 3.0e-6 /* damping factor in wave equation */ +#define GAMMAB 5.0e-4 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-6 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPAB 1.0e-6 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 1000 /* number of frames of movie */ +#define NVID 50 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.2 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.002 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.1 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 0 + +/* Color schemes */ + +#define COLOR_PALETTE 0 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 1 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 2500.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -50.0 /* amplitude of variation of hue for color scheme C_HUE */ + +/* particle properties */ + +#define PARTICLE_HUE_MIN 180.0 /* color of original particle */ +#define PARTICLE_HUE_MAX -50.0 /* color of saturated particle */ +#define PARTICLE_EMAX 1.0e12 /* max energy for particle to survive */ + +#define RANDOM_RADIUS 0 /* set to 1 for random circle radius */ +#define MOVE_PARTICLES 1 /* set to 1 for mobile particles */ +#define INERTIA 1 /* set to 1 for taking inertia into account */ +#define DT_PARTICLE 0.0000000002 /* time step for particle displacement */ +#define KSPRING 0.05 /* spring constant of particles */ +#define KWAVE 4.0 /* constant in force due to wave gradient */ +#define KREPEL 1.0 /* constant in repelling force between particles */ +#define EQUILIBRIUM_DIST 2.0 /* Lennard-Jones equilibrium distance */ +#define REPEL_RADIUS 4.0 /* radius in which repelling force acts (in units of particle radius) */ +#define DXMAX 1000.0 /* max displacement of particle in one time step */ +#define FMAX 1.0e12 /* maximal force */ +#define L_DETACH 0.25 /* spring length beyond which particles detach */ +#define DAMPING 0.00000 /* damping coefficient of particles */ +#define PARTICLE_MASS 1.0 /* mass of particle of radius MU */ + +#define HASHX 16 /* size of hashgrid in x direction */ +#define HASHY 9 /* size of hashgrid in y direction */ +#define HASHMAX 10 /* maximal number of particles per hashgrid cell */ +#define HASHGRID_PADDING 0.1 /* padding of hashgrid outside simulation window */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 1 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + diff --git a/Parameters_November21.md b/Parameters_November21.md new file mode 100644 index 0000000..7c6fdde --- /dev/null +++ b/Parameters_November21.md @@ -0,0 +1,3751 @@ +### Parameter values for YouTube simulations ### + +Created by **Nils Berglund** and optimized by **Marco Mancini** + +C code for videos on YouTube Channel https://www.youtube.com/c/NilsBerglund + +Below are parameter values used for different simulations, as well as initial conditions used in +function animation. Some simulations use variants of the published code. The list is going to be +updated gradually. + + +### 30 November 21 - Wave protection comparison 9: square grid of triangles vs square grid of circles ### + +**Program:** `wave_comparison.c` + +**Initial condition in function `animation()`:** `int_planar_wave_comp(XMIN + 0.015, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 20 /* choice of domain shape, see list in global_pdes.c */ +#define B_DOMAIN_B 40 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 0 /* pattern of circles, see list in global_pdes.c */ +#define CIRCLE_PATTERN_B 0 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 0.8 /* parameter controlling the dimensions of domain */ +#define MU 0.03 /* parameter controlling the dimensions of domain */ +#define MUB 0.04665361 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 2.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 20 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -1.65 +#define ISO_XSHIFT_RIGHT 0.4 +#define ISO_YSHIFT_LEFT -0.05 +#define ISO_YSHIFT_RIGHT -0.05 +#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.0 /* frequency of periodic excitation */ +#define AMPLITUDE 0.025 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.004 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 1.0e-8 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-6 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 5000 /* number of frames of movie */ +#define NVID 25 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 200 /* time after which to start saving frames */ +#define COMPUTE_ENERGIES 1 /* set to 1 to compute and print energies */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.02 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 1 + +/* Color schemes */ + +#define COLOR_PALETTE 12 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 2000.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -220.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 40.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 5.0 /* max value of wave amplitude */ + +``` + +### 29 November 21 - Yellow’s great escape: trajectory of one particle in a Tokarsky unilluminable room ### + +**Program:** `particle_billiard.c` + +**Initial condition in function `animation()`:** `init_drop_config(-0.95, 0.0, -0.103 + DPI/15.0, -0.1 + DPI/15.0, configs);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 30 /* choice of domain shape */ + +#define CIRCLE_PATTERN 1 /* pattern of circles */ +#define POLYLINE_PATTERN 1 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 100000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 100000 /* total number of sides of polygonal line */ +#define NCX 30 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ +#define SDEPTH 1 /* Sierpinski gastket depth */ + +#define LAMBDA 1.5 /* parameter controlling shape of domain */ +#define MU 0.002 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 1 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 1 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 1 /* set to 1 to show zoom on specific area */ +#define PRINT_PARTICLE_NUMBER 0 /* set to 1 to print number of particles */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 5500 /* number of frames of movie */ +#define TIME 1500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.00001 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 16 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 1 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.015 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 2 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 1 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ + +``` + +### 28 November 21 - Quantum of snowflake: Schrödinger’s equation in a von Koch fractal ### + +**Program:** `schrodinger.c` + +**Initial condition in function `animation()`:** `init_coherent_state(0.0, 0.0, 10.0, 0.0, 0.1, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 640 /* number of grid points on x axis */ +#define NY 360 /* number of grid points on y axis */ + +/* setting NX to WINWIDTH and NY to WINHEIGHT increases resolution */ +/* but will multiply run time by 4 */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table, see list in global_pdes.c */ + +#define B_DOMAIN 41 /* choice of domain shape */ + +#define CIRCLE_PATTERN 0 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 1 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 1.0 /* parameter controlling the dimensions of domain */ +#define MU 1.0 /* parameter controlling the dimensions of domain */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 5 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 15 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -1.65 +#define ISO_XSHIFT_RIGHT 0.4 +#define ISO_YSHIFT_LEFT -0.05 +#define ISO_YSHIFT_RIGHT -0.05 +#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard in sub_wave.c */ + +/* Physical patameters of wave equation */ + +#define DT 0.00000001 +#define HBAR 1.0 + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 1 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 2500 /* number of frames of movie */ +#define NVID 1200 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define END_FRAMES 100 /* still frames at end of movie */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 11 + + +/* Color schemes, see list in global_pdes.c */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* black background */ + +#define COLOR_SCHEME 3 /* choice of color scheme */ + +#define SCALE 1 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 150.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP 180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 2.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +``` + +### 27 November 21 - A von Koch snowflake resonating cavity with refracting walls ### + +**Program:** `wave_billiard_vonKoch.c` (variant of `wave_billiard.c`) + +**Initial condition in function `animation()`:** `init_circular_wave(0.0, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 0 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.666666666 +#define XMAX 2.666666666 /* x interval */ +#define YMIN -1.5 +#define YMAX 1.5 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 41 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 2 /* pattern of circles or polygons, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 1 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 1.0 /* parameter controlling the dimensions of domain */ +#define MU 1.0 /* parameter controlling the dimensions of domain */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 5 /* depth of computation of Menger gasket */ +#define MAXDEPTH 5 /* max depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 10 /* number of grid point for grid of disks */ +#define NGRIDY 12 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 1 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.01 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 1.0e-6 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 2 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 500 /* number of frames of movie */ +#define NVID 40 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 25 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 1 + +#define PLOT_B 0 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 11 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 1.0 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 150.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 4.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 26 November 21 - A von Koch snowflake capacitor with field lines ### + +**Program:** `heat_vonKoch.c` (variant of `heat.c`) + +**Initial condition in function `animation()`:** `init_gaussian(-1.0, 0.0, 0.1, 0.0, 0.01, phi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +/* setting NX to WINWIDTH and NY to WINHEIGHT increases resolution */ +/* but will multiply run time by 4 */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 0.5 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 27 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 0 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 0 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 1.0 /* parameter controlling the dimensions of domain */ +#define MU 0.8 /* parameter controlling the dimensions of domain */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 5 /* depth of computation of Menger gasket */ +#define MRATIO 5 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 15 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -1.65 +#define ISO_XSHIFT_RIGHT 0.4 +#define ISO_YSHIFT_LEFT -0.05 +#define ISO_YSHIFT_RIGHT -0.05 +#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard in sub_wave.c */ + +/* Physical patameters of wave equation */ + +#define DT 0.000004 +#define VISCOSITY 10.0 +#define T_OUT 2.0 /* outside temperature */ +#define T_IN 0.0 /* inside temperature */ +#define SPEED 0.0 /* speed of drift to the right */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 0 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 2000 /* number of frames of movie */ +#define NVID 50 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define BOUNDARY_WIDTH 1 /* width of billiard boundary */ + +#define PAUSE 100 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 2 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +/* Field representation */ + +#define FIELD_REP 1 + +#define F_INTENSITY 0 /* color represents intensity */ +#define F_GRADIENT 1 /* color represents norm of gradient */ + +#define DRAW_FIELD_LINES 1 /* set to 1 to draw field lines */ +#define FIELD_LINE_WIDTH 1 /* width of field lines */ +#define N_FIELD_LINES 120 /* number of field lines */ +#define FIELD_LINE_FACTOR 120 /* factor controlling precision when computing origin of field lines */ +#define REDISTRIBUTE_FIELD_LINES 0 /* set to 1 to "equidistribute" field lines according to gradient on boundary */ + +/* Color schemes, see list in global_pdes.c */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* black background */ + +#define COLOR_SCHEME 1 /* choice of color scheme */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.2 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 359.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -359.0 /* amplitude of variation of hue for color scheme C_HUE */ + +``` + +### 25 November 21 - Average energy of a wave in a von Koch snowflake fractal ### + +**Program:** `wave_billiard.c` + +**Initial condition in function `animation()`:** `init_circular_wave(0.0, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 0 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 720 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 720 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -1.125 +#define XMAX 1.125 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 41 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 2 /* pattern of circles or polygons, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 1 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 1.0 /* parameter controlling the dimensions of domain */ +#define MU 1.0 /* parameter controlling the dimensions of domain */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 5 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 10 /* number of grid point for grid of disks */ +#define NGRIDY 12 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.01 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 1.0e-6 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 1400 /* number of frames of movie */ +#define NVID 60 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 350 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 3 + +#define PLOT_B 1 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 13 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.25 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 150.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 24 November 21 - A lighthouse beam in a von Koch snowflake fractal ### + +**Program:** `particle_trajectory_vonKoch.c` (variant of `particle_trajectory.c`) + +**Initial condition in function `animation()`:** +``` + alpha = ((double)depth + (double)time)*PI/6.0; + compute_trajectories_xy(0.0, 0.0, alpha, alpha + DPI, configs, trajectory, traj_length); +``` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 30 /* choice of domain shape */ + +#define CIRCLE_PATTERN 5 /* pattern of circles */ +#define POLYLINE_PATTERN 4 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 10000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 10000 /* total number of sides of polygonal line */ +#define NCX 9 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ +#define SDEPTH 5 /* Sierpinski gastket depth */ + +#define LAMBDA 1.0 /* parameter controlling shape of domain */ +#define MU 0.0001 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 1 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define TRAJ_LENGTH 36 /* length of trajectory */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 0 /* set to 1 to show zoom on specific area */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 1480 /* number of frames of movie */ +#define TIME 2500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.00001 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 36 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 0 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.03 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 2 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 1 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ +#define ENDFRAMES 20 /* still frames at end of animation */ + +``` + +### 23 November 21 - Waves in a von Koch snowflake fractal ### + +**Program:** `wave_billiard.c` + +**Initial condition in function `animation()`:** `init_circular_wave(0.0, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 1 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 41 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 2 /* pattern of circles or polygons, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 1 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 1.0 /* parameter controlling the dimensions of domain */ +#define MU 1.0 /* parameter controlling the dimensions of domain */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 5 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 10 /* number of grid point for grid of disks */ +#define NGRIDY 12 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.01 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 1.0e-6 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 2900 /* number of frames of movie */ +#define NVID 40 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 350 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 0 + +#define PLOT_B 1 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 13 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.25 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 150.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 8.0 /* scale of color scheme bar */ +#define COLORBAR_RANGE_B 12.0 /* scale of color scheme bar for 2nd part */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 22 November 21 - Billiard in a von Koch snowflake fractal ### + +**Program:** `particle_vonKoch.c` (variant of `particle_billiard.c`) + +**Initial condition in function `animation()`:** `init_drop_config(0.0, 0.0, -PI, PI, configs);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 30 /* choice of domain shape */ + +#define CIRCLE_PATTERN 1 /* pattern of circles */ +#define POLYLINE_PATTERN 4 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 100000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 100000 /* total number of sides of polygonal line */ +#define NCX 30 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ +#define SDEPTH 5 /* Sierpinski gastket depth */ + +#define LAMBDA 1.0 /* parameter controlling shape of domain */ +#define MU 0.0001 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 10000 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 0 /* set to 1 to show zoom on specific area */ +#define PRINT_PARTICLE_NUMBER 0 /* set to 1 to print number of particles */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 1000 /* number of frames of movie */ +#define TIME 1500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.000005 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 11 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 12 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 0 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.01 /* length of velocity vectors */ +#define BILLIARD_WIDTH 1 /* width of billiard */ +#define PARTICLE_WIDTH 2 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 0 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ +#define END_FRAMES 50 /* number of still frames at end of movie */ + +``` + +### 21 November 21 - Waves hitting a randomized square grid of hexagons ### + +**Program:** `wave_billiard.c` + +**Initial condition in function `animation()`:** `init_planar_wave(XMIN + 0.02, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 1 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 40 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 2 /* pattern of circles or polygons, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define RANDOM_POLY_ANGLE 1 /* set to 1 to randomize angle of polygons */ + +#define LAMBDA 0.7 /* parameter controlling the dimensions of domain */ +#define MU 0.06 /* parameter controlling the dimensions of domain */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 2.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 10 /* number of grid point for grid of disks */ +#define NGRIDY 12 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.01 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 1.0e-6 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 2200 /* number of frames of movie */ +#define NVID 50 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 50 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 0 + +#define PLOT_B 1 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 14 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.1 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 100.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 20.0 /* scale of color scheme bar */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 20 November 21 - A lighthouse beam in a mirrored hexagon ### + +**Program:** `particle_trajectory.c` + +**Initial condition in function `animation()`:** +``` + x = 0.0; + y = 0.0; + alpha = (1.0/6.0 + (double)time/3.0)*PI; + compute_trajectories_xy(x, y, alpha, alpha + DPI, configs, trajectory, traj_length); +``` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 8 /* choice of domain shape */ + +#define CIRCLE_PATTERN 5 /* pattern of circles */ +#define POLYLINE_PATTERN 1 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 1000 /* total number of sides of polygonal line */ +#define NCX 9 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ +#define SDEPTH 4 /* Sierpinski gastket depth */ + +#define LAMBDA 1.0 /* parameter controlling shape of domain */ +#define MU 0.02 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 1 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define TRAJ_LENGTH 36 /* length of trajectory */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 0 /* set to 1 to show zoom on specific area */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 3500 /* number of frames of movie */ +#define TIME 2500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.00001 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 36 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 0 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.03 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 2 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 1 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ + +``` + +### 19 November 21 - Waves starting off center in a four-sided parabolic resonator ### + +**Program:** `wave_billiard.c` + +**Initial condition in function `animation()`:** `init_circular_wave(0.1, 0.05, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 1 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 32 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ + +#define LAMBDA 0.0 /* parameter controlling the dimensions of domain */ +#define MU 1.0 /* parameter controlling the dimensions of domain */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY 0.5 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 16 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.02 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 5.0e-3 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 2 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 3350 /* number of frames of movie */ +#define NVID 40 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 0 + +#define PLOT_B 1 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.25 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 120.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 7.5 /* scale of color scheme bar */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 18 November 21 - Mystery billiard 11 ### + +**Program:** `mystery_billiard.c` + +**Initial condition in function `animation()`:** `init_drop_config(-1.5, 0.0, -PI, PI, configs);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 30 /* choice of domain shape */ + +#define CIRCLE_PATTERN 1 /* pattern of circles */ +#define POLYLINE_PATTERN 3 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 0 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 10000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 10000 /* total number of sides of polygonal line */ +#define NCX 30 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ +#define SDEPTH 4 /* Sierpinski gastket depth */ + +#define LAMBDA 1.8 /* parameter controlling shape of domain */ +#define MU 0.01 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 0 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 2000 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 0 /* set to 1 to show zoom on specific area */ +#define PRINT_PARTICLE_NUMBER 0 /* set to 1 to print number of particles */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 5000 /* number of frames of movie */ +#define TIME 1500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.0000075 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 14 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 16 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 1 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.025 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 2 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 0 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ +#define FINALFRAMES 100 /* number of still frames at the end */ + +``` + +### 17 November 21 - Wave meets triangular grid of triangular obstacles ### + +**Program:** `wave_billiard.c` + +**Initial condition in function `animation()`:** `init_planar_wave(XMIN + 0.02, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 0 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 720 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -1.125 +#define XMAX 1.125 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 40 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 1 /* pattern of circles or polygons, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ + +#define LAMBDA 0.7 /* parameter controlling the dimensions of domain */ +#define MU 0.07 /* parameter controlling the dimensions of domain */ +#define NPOLY 3 /* number of sides of polygon */ +#define APOLY 2.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 10 /* number of grid point for grid of disks */ +#define NGRIDY 12 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.01 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 1.0e-6 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 1200 /* number of frames of movie */ +#define NVID 50 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 25 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.02 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 1 + +#define PLOT_B 1 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 13 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.04 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 100.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 40.0 /* scale of color scheme bar */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 16 November 21 - Mystery billiard 10 ### + +**Program:** `mystery_billiard.c` + +**Initial condition in function `animation()`:** `init_drop_config(0.75, 0.0, PI-0.1, PI+0.1, configs);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 30 /* choice of domain shape */ + +#define CIRCLE_PATTERN 1 /* pattern of circles */ +#define POLYLINE_PATTERN 2 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 1000 /* total number of sides of polygonal line */ +#define NCX 30 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ + +#define LAMBDA 1.2 /* parameter controlling shape of domain */ +#define MU 0.6 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 0 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 1000 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 0 /* set to 1 to show zoom on specific area */ +#define PRINT_PARTICLE_NUMBER 0 /* set to 1 to print number of particles */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 4500 /* number of frames of movie */ +#define TIME 1500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.0000075 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 8 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 0 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.025 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 2 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 0 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ + +``` + +### 15 November 21 - A fiery wave hitting random obstacles ### + +**Program:** `wave_billiard.c` + +**Initial condition in function `animation()`:** `init_planar_wave(XMIN + 0.02, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 0 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 20 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 2 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ + +#define LAMBDA 0.5 /* parameter controlling the dimensions of domain */ +#define MU 0.03 /* parameter controlling the dimensions of domain */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY 0.5 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 16 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 1 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.01 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 1.0e-6 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 3 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 3350 /* number of frames of movie */ +#define NVID 35 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 75 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.02 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 1 + +#define PLOT_B 1 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 13 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.05 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 100.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 40.0 /* scale of color scheme bar */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 14 November 21 - The origin of the xenomorph: wave in a rotating ellipse ### + +**Program:** `wave_billiard_rotate.c` + +**Initial condition in function `animation()`:** `init_circular_wave(0.0, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 0 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -3.0 +#define XMAX 3.0 /* x interval */ +#define YMIN -1.6875 +#define YMAX 1.6875 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 1 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ + +#define LAMBDA 1.5 /* parameter controlling the dimensions of domain */ +#define MU 0.9 /* parameter controlling the dimensions of domain */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY -0.02 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 16 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define ROTATION 0.0014 /* rotation angle per frame */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -1.65 +#define ISO_XSHIFT_RIGHT 0.4 +#define ISO_YSHIFT_LEFT -0.05 +#define ISO_YSHIFT_RIGHT -0.05 +#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.02 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 5.0e-3 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 2 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 6250 /* number of frames of movie */ +#define NVID 40 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0005 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.04 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 1 + +#define PLOT_B 0 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 12 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 1 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.8 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 100.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 2.8 /* scale of color scheme bar */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 13 November 21 - Trajectories on a translation surface of genus 2 ### + +**Program:** `particle_trajectory.c` + +**Initial condition in function `animation()`:** +``` + x = -0.5; + y = -0.5; + alpha = time*PI; + compute_trajectories_xy(x, y, alpha, alpha + DPI, configs, trajectory, traj_length); +``` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 13 /* choice of domain shape */ + +#define CIRCLE_PATTERN 5 /* pattern of circles */ +#define POLYLINE_PATTERN 1 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 1000 /* total number of sides of polygonal line */ +#define NCX 9 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ + +#define LAMBDA 1.5 /* parameter controlling shape of domain */ +#define MU 0.02 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 16 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define TRAJ_LENGTH 10 /* length of trajectory */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 0 /* set to 1 to show zoom on specific area */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 3000 /* number of frames of movie */ +#define TIME 2500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.00001 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 64 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 1 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.03 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 2 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 1 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ + +``` + +### 12 November 21 - Classics revisited: Wave in an ellipse starting from a focus ### + +**Program:** `wave_billiard.c` + +**Initial condition in function `animation()`:** `init_circular_wave(sqrt(LAMBDA*LAMBDA - 1.0), 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 0 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 1 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ + +#define LAMBDA 1.5 /* parameter controlling the dimensions of domain */ +#define MU 1.0 /* parameter controlling the dimensions of domain */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY 0.5 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 16 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.02 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 5.0e-3 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 2 + +/* Parameters for length and speed of simulation */ + +// #define NSTEPS 500 /* number of frames of movie */ +#define NSTEPS 4200 /* number of frames of movie */ +#define NVID 40 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 0 + +#define PLOT_B 1 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 11 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.25 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 120.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 7.5 /* scale of color scheme bar */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 11 November 21 - Stringer Bell's demise: trajectories in a Tokarsky room with a moving shooter ### + +**Program:** `particle_trajectory.c` + +**Initial condition in function `animation()`:** + +``` + x = -0.95 - 0.2*time; + y = 0.5 - 0.5*(1.0 - time); + alpha = argument(x + 0.95, y) - PI; + compute_trajectories_xy(x, y, alpha, DPI + alpha, configs, trajectory, traj_length); +``` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 30 /* choice of domain shape */ + +#define CIRCLE_PATTERN 5 /* pattern of circles */ +#define POLYLINE_PATTERN 1 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 1000 /* total number of sides of polygonal line */ +#define NCX 9 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ + +#define LAMBDA 1.5 /* parameter controlling shape of domain */ +#define MU 0.02 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 10000 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define TRAJ_LENGTH 48 /* length of trajectory */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 1 /* set to 1 to show zoom on specific area */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 2000 /* number of frames of movie */ +#define TIME 2500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.00001 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 14 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 64 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 1 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.03 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 2 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 1 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ + +``` + +### 10 November 21 - The power of Inti: Four waves in a rotating four-sided parabolic resonator ### + +**Program:** `wave_billiard_rotate.c` + +**Initial condition in function `animation()`:** +``` + init_circular_wave(0.35, 0.35, phi, psi, xy_in); + add_circular_wave(-1.0, -0.35, 0.35, phi, psi, xy_in); + add_circular_wave(1.0, -0.35, -0.35, phi, psi, xy_in); + add_circular_wave(-1.0, 0.35, -0.35, phi, psi, xy_in); +``` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 1 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 32 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ + +#define LAMBDA 0.0 /* parameter controlling the dimensions of domain */ +#define MU 0.9 /* parameter controlling the dimensions of domain */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY -0.02 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 16 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define ROTATION 0.0015 /* rotation angle per frame */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -1.65 +#define ISO_XSHIFT_RIGHT 0.4 +#define ISO_YSHIFT_LEFT -0.05 +#define ISO_YSHIFT_RIGHT -0.05 +#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.02 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 5.0e-3 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 2 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 2600 /* number of frames of movie */ +#define NVID 50 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.00025 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.03 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 0 + +#define PLOT_B 1 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.2 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 100.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 7.5 /* scale of color scheme bar */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 9 November 21 - Particles stating off center in a parabolic resonator ### + +**Program:** `particle_billiard.c` + +**Initial condition in function `animation()`:** `init_drop_config(0.03, 0.02, 0.0, DPI, configs);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 720 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -1.125 +#define XMAX 1.125 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 15 /* choice of domain shape */ + +#define CIRCLE_PATTERN 1 /* pattern of circles */ +#define POLYLINE_PATTERN 1 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 1000 /* total number of sides of polygonal line */ +#define NCX 30 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ + +#define LAMBDA 0.0 /* parameter controlling shape of domain */ +#define MU 1.0 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 20000 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 0 /* set to 1 to show zoom on specific area */ +#define PRINT_PARTICLE_NUMBER 0 /* set to 1 to print number of particles */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 1350 /* number of frames of movie */ +#define TIME 1500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.00001 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 16 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 0 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.025 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 2 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 0 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ + +``` + +### 8 November 21 - Chaotic waves in a diamond resonator ### + +**Program:** `wave_billiard.c` + +**Initial condition in function `animation()`:** `init_circular_wave(0.0, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 1 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 4 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ + +#define LAMBDA 2.0 /* parameter controlling the dimensions of domain */ +#define MU 0.5 /* parameter controlling the dimensions of domain */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY 0.5 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 16 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.02 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 5.0e-3 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 2 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 2300 /* number of frames of movie */ +#define NVID 40 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_WAVELENGTH 0.015 /* wavelength of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 0 + +#define PLOT_B 1 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 15 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.25 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 120.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 7.5 /* scale of color scheme bar */ +#define ROTATE_COLOR_SCHEME 0 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 7 November 21 - Don't s̶h̶u̶t̶ shoot me down (part 2): Particles with trails in a Tokarsky room ### + +**Program:** `particle_billiard.c` + +**Initial condition in function `animation()`:** `init_drop_config(-0.95, 0.0, -0.1, -0.1 + DPI, configs);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 30 /* choice of domain shape */ + +#define CIRCLE_PATTERN 1 /* pattern of circles */ +#define POLYLINE_PATTERN 1 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 1000 /* total number of sides of polygonal line */ +#define NCX 30 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ + +#define LAMBDA 1.5 /* parameter controlling shape of domain */ +#define MU 0.0035 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 16 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 1 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 1 /* set to 1 to show zoom on specific area */ +#define PRINT_PARTICLE_NUMBER 1 /* set to 1 to print number of particles */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 3000 /* number of frames of movie */ +#define TIME 1500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.00001 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 64 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 1 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.015 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 2 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 1 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ + +``` + +### 6 November 21 - Wave amplitude and average energy in homophonic drums ### + +**Program:** `wave_billiard.c` + +**Initial condition in function `animation()`:** `init_circular_wave_xplusminus(startleft[0], startleft[1], startright[0], startright[1], phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 1 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 38 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ + +#define LAMBDA 1.5 /* parameter controlling the dimensions of domain */ +#define MU 0.5 /* parameter controlling the dimensions of domain */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY 0.5 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 16 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.02 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 5.0e-3 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 2 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 3600 /* number of frames of movie */ +#define NVID 40 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.02 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 0 + +#define PLOT_B 3 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 16 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.25 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 150.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 7.5 /* scale of color scheme bar */ +#define ROTATE_COLOR_SCHEME 1 /* set to 1 to draw color scheme horizontally */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 5 November 21 - Don’t s̶h̶u̶t̶ shoot me down: Particles in a Tokarsky unilluminable room ### + +**Program:** `particle_billiard.c` + +**Initial condition in function `animation()`:** `init_drop_config(-0.95, 0.0, PI, 3.0*PI, configs);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 30 /* choice of domain shape */ + +#define CIRCLE_PATTERN 1 /* pattern of circles */ +#define POLYLINE_PATTERN 1 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 1 /* set to 1 for circular scatterers to be absorbing */ +#define ABSORBING_CORNER_RADIUS 0.0 /* radius of absorbing corners in polygonal line */ + +#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 1000 /* total number of sides of polygonal line */ +#define NCX 30 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ + +#define LAMBDA 1.5 /* parameter controlling shape of domain */ +#define MU 0.01 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 5000 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ +#define SHOWZOOM 1 /* set to 1 to show zoom on specific area */ +#define PRINT_PARTICLE_NUMBER 1 /* set to 1 to print number of particles */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 1150 /* number of frames of movie */ +#define TIME 3000 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.000005 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 64 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 1 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.025 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 3 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 1 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ + +``` + +### 4 November 21 - A rotating hexagonal parabolic resonator ### + +**Program:** `wave_billiard_rotate.c` + +**Initial condition in function `animation()`:** `init_circular_wave(0.0, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 1 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 32 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ + +#define LAMBDA 0.0 /* parameter controlling the dimensions of domain */ +#define MU 1.0 /* parameter controlling the dimensions of domain */ +#define NPOLY 6 /* number of sides of polygon */ +#define APOLY -0.02 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 16 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define ROTATION 0.00275 /* rotation angle per frame */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -1.65 +#define ISO_XSHIFT_RIGHT 0.4 +#define ISO_YSHIFT_LEFT -0.05 +#define ISO_YSHIFT_RIGHT -0.05 +#define ISO_SCALE 0.85 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.02 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 5.0e-3 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 2 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 4350 /* number of frames of movie */ +#define NVID 50 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.00025 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.02 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 1 + +#define PLOT_B 0 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 10 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.2 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 50.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 1 /* set to 1 to plot the color scheme */ +#define COLORBAR_RANGE 7.5 /* scale of color scheme bar */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + +### 3 November 21 - Trajectories in a triangular billiard ### + +**Program:** `particle_trajectory.c` + +**Initial condition in function `animation()`:** +``` + alpha = PI*1.25; + x = -1.0 + 0.5*cos(DPI*time + alpha); + y = LAMBDA - 2.0 + 0.5*sin(DPI*time + alpha); + alpha = PI/3.0; + compute_trajectories_xy(x, y, alpha, DPI + alpha, configs, trajectory, traj_length); + +``` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 5 /* choice of domain shape */ + +#define CIRCLE_PATTERN 5 /* pattern of circles */ +#define POLYLINE_PATTERN 1 /* pattern of polyline */ + +#define ABSORBING_CIRCLES 0 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NMAXPOLY 1000 /* total number of sides of polygonal line */ +#define NCX 9 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ + +#define LAMBDA 1.732050808 /* sqrt(3) - parameter controlling shape of domain */ +#define MU 0.04 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 24 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define TRAJ_LENGTH 48 /* length of trajectory */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 3000 /* number of frames of movie */ +#define TIME 2500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.00001 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 14 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 64 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 1 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.03 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 2 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 1 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ + +``` + +### 2 November 21 - Classics revisited: circular wave starting from the center of an ellipse ### + +**Program:** `wave_billiard.c` + +**Initial condition in function `animation()`:** `init_circular_wave(0.0, 0.0, phi, psi, xy_in);` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ +#define DOUBLE_MOVIE 0 /* set to 1 to produce movies for wave height and energy simultaneously */ + +/* General geometrical parameters */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define NX 1280 /* number of grid points on x axis */ +#define NY 720 /* number of grid points on y axis */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define JULIA_SCALE 1.0 /* scaling for Julia sets */ + +/* Choice of the billiard table */ + +#define B_DOMAIN 1 /* choice of domain shape, see list in global_pdes.c */ + +#define CIRCLE_PATTERN 7 /* pattern of circles, see list in global_pdes.c */ + +#define P_PERCOL 0.25 /* probability of having a circle in C_RAND_PERCOL arrangement */ +#define NPOISSON 300 /* number of points for Poisson C_RAND_POISSON arrangement */ + +#define LAMBDA 1.5 /* parameter controlling the dimensions of domain */ +#define MU 0.5 /* parameter controlling the dimensions of domain */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY 0.5 /* angle by which to turn polygon, in units of Pi/2 */ +#define MDEPTH 4 /* depth of computation of Menger gasket */ +#define MRATIO 3 /* ratio defining Menger gasket */ +#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */ +#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NGRIDX 16 /* number of grid point for grid of disks */ +#define NGRIDY 20 /* number of grid point for grid of disks */ + +#define X_SHOOTER -0.2 +#define Y_SHOOTER -0.6 +#define X_TARGET 0.4 +#define Y_TARGET 0.7 /* shooter and target positions in laser fight */ + +#define ISO_XSHIFT_LEFT -2.9 +#define ISO_XSHIFT_RIGHT 1.4 +#define ISO_YSHIFT_LEFT -0.15 +#define ISO_YSHIFT_RIGHT -0.15 +#define ISO_SCALE 0.5 /* coordinates for isospectral billiards */ + +/* You can add more billiard tables by adapting the functions */ +/* xy_in_billiard and draw_billiard below */ + +/* Physical parameters of wave equation */ + +#define TWOSPEEDS 0 /* set to 1 to replace hardcore boundary by medium with different speed */ +#define OSCILLATE_LEFT 0 /* set to 1 to add oscilating boundary condition on the left */ +#define OSCILLATE_TOPBOT 0 /* set to 1 to enforce a planar wave on top and bottom boundary */ + +#define OMEGA 0.002 /* frequency of periodic excitation */ +#define AMPLITUDE 1.0 /* amplitude of periodic excitation */ +#define COURANT 0.02 /* Courant number */ +#define COURANTB 0.02 /* Courant number in medium B */ +#define GAMMA 0.0 /* damping factor in wave equation */ +#define GAMMAB 5.0e-3 /* damping factor in wave equation */ +#define GAMMA_SIDES 1.0e-4 /* damping factor on boundary */ +#define GAMMA_TOPBOT 1.0e-7 /* damping factor on boundary */ +#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */ +#define KAPPA_SIDES 5.0e-4 /* "elasticity" term on absorbing boundary */ +#define KAPPA_TOPBOT 0.0 /* "elasticity" term on absorbing boundary */ +/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */ +/* The physical damping coefficient is given by GAMMA/(DT)^2 */ +/* Increasing COURANT speeds up the simulation, but decreases accuracy */ +/* For similar wave forms, COURANT^2*GAMMA should be kept constant */ + +/* Boundary conditions, see list in global_pdes.c */ + +#define B_COND 2 + +/* Parameters for length and speed of simulation */ + +#define NSTEPS 4600 /* number of frames of movie */ +#define NVID 50 /* number of iterations between images displayed on screen */ +#define NSEG 100 /* number of segments of boundary */ +#define INITIAL_TIME 0 /* time after which to start saving frames */ +#define BOUNDARY_WIDTH 2 /* width of billiard boundary */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1 /* final sleeping time */ +#define MID_FRAMES 20 /* number of still frames between parts of two-part movie */ +#define END_FRAMES 100 /* number of still frames at end of movie */ + +/* Parameters of initial condition */ + +#define INITIAL_AMP 0.75 /* amplitude of initial condition */ +#define INITIAL_VARIANCE 0.0003 /* variance of initial condition */ +#define INITIAL_WAVELENGTH 0.02 /* wavelength of initial condition */ + +/* Plot type, see list in global_pdes.c */ + +#define PLOT 1 + +#define PLOT_B 1 /* plot type for second movie */ + +/* Color schemes */ + +#define COLOR_PALETTE 12 /* Color palette, see list in global_pdes.c */ + +#define BLACK 1 /* background */ + +#define COLOR_SCHEME 3 /* choice of color scheme, see list in global_pdes.c */ + +#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */ +#define SLOPE 0.35 /* sensitivity of color on wave amplitude */ +#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */ +#define E_SCALE 100.0 /* scaling factor for energy representation */ + +#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */ +#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */ +#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */ +#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */ +#define HUEMEAN 180.0 /* mean value of hue for color scheme C_HUE */ +#define HUEAMP -180.0 /* amplitude of variation of hue for color scheme C_HUE */ + +#define DRAW_COLOR_SCHEME 0 /* set to 1 to plot the color scheme */ + +#define SAVE_TIME_SERIES 0 /* set to 1 to save wave time series at a point */ + +/* For debugging purposes only */ +#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */ +#define VMAX 10.0 /* max value of wave amplitude */ + +``` + + +### 1 November 21 - Particles in a four-sided eccentric parabolic resonator ### + +**Program:** `particle_billiard.c` + +**Initial condition in function `animation()`:** +``` + init_partial_drop_config(LAMBDA, 0.0, 0.0, DPI, 0, NPART/4, 0, configs, color, newcolor); + init_partial_drop_config(-LAMBDA, 0.0, 0.0, DPI, NPART/4, NPART/2, 0, configs, color, newcolor); + init_partial_drop_config(0.0, LAMBDA, 0.0, DPI, NPART/2, 3*NPART/4, 0, configs, color, newcolor); + init_partial_drop_config(0.0, -LAMBDA, 0.0, DPI, 3*NPART/4, NPART, 0, configs, color, newcolor); +``` + +``` +#define MOVIE 1 /* set to 1 to generate movie */ + +#define WINWIDTH 1280 /* window width */ +#define WINHEIGHT 720 /* window height */ + +#define XMIN -2.0 +#define XMAX 2.0 /* x interval */ +#define YMIN -1.125 +#define YMAX 1.125 /* y interval for 9/16 aspect ratio */ + +#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */ + +/* Choice of the billiard table, see global_particles.c */ + +#define B_DOMAIN 15 /* choice of domain shape */ + +#define CIRCLE_PATTERN 2 /* pattern of circles */ + +#define ABSORBING_CIRCLES 0 /* set to 1 for circular scatterers to be absorbing */ + +#define NMAXCIRCLES 1000 /* total number of circles (must be at least NCX*NCY for square grid) */ +#define NCX 30 /* number of circles in x direction */ +#define NCY 20 /* number of circles in y direction */ +#define NPOISSON 500 /* number of points for Poisson C_RAND_POISSON arrangement */ +#define NGOLDENSPIRAL 2000 /* max number of points for C_GOLDEN_SPIRAL arrandement */ + +#define LAMBDA 0.3 /* parameter controlling shape of domain */ +#define MU 0.7 /* second parameter controlling shape of billiard */ +#define FOCI 1 /* set to 1 to draw focal points of ellipse */ +#define NPOLY 4 /* number of sides of polygon */ +#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */ +#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */ +#define DRAW_CONSTRUCTION_LINES 0 /* set to 1 to draw additional construction lines for billiard */ +#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */ + +#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */ +#define DEBUG 0 /* draw trajectories, for debugging purposes */ + +/* Simulation parameters */ + +#define NPART 10000 /* number of particles */ +#define NPARTMAX 100000 /* maximal number of particles after resampling */ +#define LMAX 0.01 /* minimal segment length triggering resampling */ +#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */ +#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */ +#define SHOWTRAILS 0 /* set to 1 to keep trails of the particles */ +#define TEST_ACTIVE 1 /* set to 1 to test whether particle is in billiard */ + +#define NSTEPS 4600 /* number of frames of movie */ +#define TIME 2500 /* time between movie frames, for fluidity of real-time simulation */ +#define DPHI 0.0000025 /* integration step */ +#define NVID 150 /* number of iterations between images displayed on screen */ + +/* Decreasing TIME accelerates the animation and the movie */ +/* For constant speed of movie, TIME*DPHI should be kept constant */ +/* However, increasing DPHI too much deterioriates quality of simulation */ +/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */ +/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */ + +/* Colors and other graphical parameters */ + +#define COLOR_PALETTE 1 /* Color palette, see list in global_pdes.c */ + +#define NCOLORS 64 /* number of colors */ +#define COLORSHIFT 0 /* hue of initial color */ +#define RAINBOW_COLOR 0 /* set to 1 to use different colors for all particles */ +#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */ +#define NSEG 100 /* number of segments of boundary */ +#define LENGTH 0.02 /* length of velocity vectors */ +#define BILLIARD_WIDTH 2 /* width of billiard */ +#define PARTICLE_WIDTH 1 /* width of particles */ +#define FRONT_WIDTH 3 /* width of wave front */ + +#define BLACK 1 /* set to 1 for black background */ +#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */ +#define OUTER_COLOR 270.0 /* color outside billiard */ +#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */ +#define PAINT_EXT 1 /* set to 1 to paint exterior */ + +#define PAUSE 1000 /* number of frames after which to pause */ +#define PSLEEP 1 /* sleep time during pause */ +#define SLEEP1 1 /* initial sleeping time */ +#define SLEEP2 1000 /* final sleeping time */ + +```