2021-07-27 18:56:02 +02:00
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### Parameter values for YouTube simulations ###
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Created by **Nils Berglund** and optimized by **Marco Mancini**
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C code for videos on YouTube Channel https://www.youtube.com/c/NilsBerglund
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Below are parameter values used for different simulations, as well as initial conditions used in
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function animation. Some simulations use variants of the published code. The list is going to be
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updated gradually.
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2021-07-27 19:40:10 +02:00
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### 19 July 21 - 10,000 particles on a genus 10 surface ###
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**Program:** `particle_billiard.c`
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```
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#define MOVIE 1 /* set to 1 to generate movie */
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#define WINWIDTH 1280 /* window width */
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#define WINHEIGHT 720 /* window height */
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#define XMIN -2.0
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#define XMAX 2.0 /* x interval */
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#define YMIN -1.125
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#define YMAX 1.125 /* y interval for 9/16 aspect ratio */
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#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */
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/* Choice of the billiard table */
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#define B_DOMAIN 14 /* choice of domain shape */
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#define D_RECTANGLE 0 /* rectangular domain */
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#define D_ELLIPSE 1 /* elliptical domain */
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#define D_STADIUM 2 /* stadium-shaped domain */
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#define D_SINAI 3 /* Sinai billiard */
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#define D_DIAMOND 4 /* diamond-shaped billiard */
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#define D_TRIANGLE 5 /* triangular billiard */
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#define D_ANNULUS 7 /* annulus */
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#define D_POLYGON 8 /* polygon */
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#define D_REULEAUX 9 /* Reuleaux and star shapes */
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#define D_FLOWER 10 /* Bunimovich flower */
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#define D_ALT_REU 11 /* alternating between star and Reuleaux */
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#define D_ANGLE 12 /* angular sector */
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#define D_LSHAPE 13 /* L-shaped billiard for conical singularity */
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#define D_GENUSN 14 /* polygon with identifies opposite sides */
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#define LAMBDA 0.75 /* parameter controlling shape of billiard */
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#define MU 0.1 /* second parameter controlling shape of billiard */
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#define FOCI 1 /* set to 1 to draw focal points of ellipse */
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#define NPOLY 40 /* number of sides of polygon */
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#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */
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#define DRAW_BILLIARD 1 /* set to 1 to draw billiard */
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#define DRAW_CONSTRUCTION_LINES 1 /* set to 1 to draw additional construction lines for billiard */
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#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */
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#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */
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#define DEBUG 0 /* draw trajectories, for debugging purposes */
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/* Simulation parameters */
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#define NPART 10002 /* number of particles */
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#define NPARTMAX 100000 /* maximal number of particles after resampling */
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#define LMAX 0.01 /* minimal segment length triggering resampling */
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#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */
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#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */
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#define NSTEPS 7650 /* number of frames of movie */
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#define TIME 1000 /* time between movie frames, for fluidity of real-time simulation */
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// #define DPHI 0.000002 /* integration step */
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// #define DPHI 0.00002 /* integration step */
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#define DPHI 0.000005 /* integration step */
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#define NVID 150 /* number of iterations between images displayed on screen */
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/* Decreasing TIME accelerates the animation and the movie */
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/* For constant speed of movie, TIME*DPHI should be kept constant */
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/* However, increasing DPHI too much deterioriates quality of simulation */
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/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */
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/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */
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/* Colors and other graphical parameters */
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#define NCOLORS 20 /* number of colors */
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#define COLORSHIFT 200 /* hue of initial color */
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#define RAINBOW_COLOR 1 /* set to 1 to use different colors for all particles */
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#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */
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#define NSEG 100 /* number of segments of boundary */
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#define LENGTH 0.02 /* length of velocity vectors */
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#define BILLIARD_WIDTH 3 /* width of billiard */
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#define PARTICLE_WIDTH 2 /* width of particles */
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#define FRONT_WIDTH 3 /* width of wave front */
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#define BLACK 1 /* set to 1 for black background */
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#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */
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#define OUTER_COLOR 270.0 /* color outside billiard */
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#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */
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#define PAUSE 1000 /* number of frames after which to pause */
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#define PSLEEP 1 /* sleep time during pause */
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#define SLEEP1 1 /* initial sleeping time */
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#define SLEEP2 1000 /* final sleeping time */
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#define PI 3.141592654
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#define DPI 6.283185307
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#define PID 1.570796327
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init_drop_config(0.0, 0.0, PI, DPI, configs);
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```
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2021-07-27 19:07:11 +02:00
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### 18 July 21 - Refraction (and diffraction) through a raindrop ###
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2021-07-27 18:56:02 +02:00
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2021-07-27 19:09:01 +02:00
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**Program:** `wave_billiard.c`
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2021-07-27 18:56:02 +02:00
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2021-07-27 19:23:45 +02:00
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```
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#define MOVIE 1 /* set to 1 to generate movie */
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2021-07-27 19:05:38 +02:00
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/* General geometrical parameters */
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#define WINWIDTH 1280 /* window width */
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#define WINHEIGHT 720 /* window height */
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#define NX 1280 /* number of grid points on x axis */
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#define NY 720 /* number of grid points on y axis */
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#define XMIN -1.8
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#define XMAX 1.8 /* x interval */
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#define YMIN -1.0125
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#define YMAX 1.0125 /* y interval for 9/16 aspect ratio */
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#define JULIA_SCALE 1.0 /* scaling for Julia sets */
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/* Choice of the billiard table */
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2021-07-27 18:56:02 +02:00
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#define B_DOMAIN 3 /* choice of domain shape */
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#define D_RECTANGLE 0 /* rectangular domain */
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#define D_ELLIPSE 1 /* elliptical domain */
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#define D_STADIUM 2 /* stadium-shaped domain */
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#define D_SINAI 3 /* Sinai billiard */
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#define D_DIAMOND 4 /* diamond-shaped billiard */
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#define D_TRIANGLE 5 /* triangular billiard */
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#define D_FLAT 6 /* flat interface */
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#define D_ANNULUS 7 /* annulus */
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#define D_POLYGON 8 /* polygon */
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#define D_YOUNG 9 /* Young diffraction slits */
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#define D_GRATING 10 /* diffraction grating */
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#define D_EHRENFEST 11 /* Ehrenfest urn type geometry */
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#define D_DISK_GRID 12 /* grid of disks */
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#define D_DISK_HEX 13 /* haxagonl grid of disks */
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#define D_DISK_PERCOL 14 /* random grid of percolation type */
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#define D_MENGER 15 /* Menger-Sierpinski carpet */
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#define D_JULIA_INT 16 /* interior of Julia set */
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#define D_MENGER_ROTATED 17 /* rotated Menger-Sierpinski carpet */
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/* Billiard tables for heat equation */
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#define D_ANNULUS_HEATED 21 /* annulus with different temperatures */
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#define D_MENGER_HEATED 22 /* Menger gasket with different temperatures */
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#define D_MENGER_H_OPEN 23 /* Menger gasket with different temperatures and larger domain */
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#define D_MANDELBROT 24 /* Mandelbrot set */
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#define D_JULIA 25 /* Julia set */
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#define D_MANDELBROT_CIRCLE 26 /* Mandelbrot set with circular conductor */
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#define LAMBDA 0.75 /* parameter controlling the dimensions of domain */
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#define MU 0.025 /* parameter controlling the dimensions of domain */
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#define NPOLY 8 /* number of sides of polygon */
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#define APOLY 1.0 /* angle by which to turn polygon, in units of Pi/2 */
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#define MDEPTH 4 /* depth of computation of Menger gasket */
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#define MRATIO 3 /* ratio defining Menger gasket */
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#define MANDELLEVEL 1000 /* iteration level for Mandelbrot set */
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#define MANDELLIMIT 10.0 /* limit value for approximation of Mandelbrot set */
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#define FOCI 1 /* set to 1 to draw focal points of ellipse */
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#define NGRIDX 15 /* number of grid point for grid of disks */
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#define NGRIDY 20 /* number of grid point for grid of disks */
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/* You can add more billiard tables by adapting the functions */
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/* xy_in_billiard and draw_billiard below */
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/* Physical parameters of wave equation */
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#define TWOSPEEDS 1 /* set to 1 to replace hardcore boundary by medium with different speed */
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#define OMEGA 0.9 /* frequency of periodic excitation */
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#define COURANT 0.01 /* Courant number */
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#define COURANTB 0.003 /* Courant number in medium B */
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#define GAMMA 0.0 /* damping factor in wave equation */
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#define GAMMA_BC 1.0e-4 /* damping factor on boundary */
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#define KAPPA 0.0 /* "elasticity" term enforcing oscillations */
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#define KAPPA_BC 5.0e-4 /* "elasticity" term on absorbing boundary */
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/* The Courant number is given by c*DT/DX, where DT is the time step and DX the lattice spacing */
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/* The physical damping coefficient is given by GAMMA/(DT)^2 */
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/* Increasing COURANT speeds up the simulation, but decreases accuracy */
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/* For similar wave forms, COURANT^2*GAMMA should be kept constant */
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/* Boundary conditions */
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#define B_COND 3
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#define BC_DIRICHLET 0 /* Dirichlet boundary conditions */
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#define BC_PERIODIC 1 /* periodic boundary conditions */
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#define BC_ABSORBING 2 /* absorbing boundary conditions (beta version) */
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#define BC_VPER_HABS 3 /* vertically periodic and horizontally absorbing boundary conditions */
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/* For debugging purposes only */
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#define FLOOR 0 /* set to 1 to limit wave amplitude to VMAX */
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#define VMAX 10.0 /* max value of wave amplitude */
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/* Parameters for length and speed of simulation */
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#define NSTEPS 9000 /* number of frames of movie */
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#define NVID 50 /* number of iterations between images displayed on screen */
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#define NSEG 100 /* number of segments of boundary */
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#define INITIAL_TIME 300 /* time after which to start saving frames */
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#define PAUSE 1000 /* number of frames after which to pause */
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#define PSLEEP 1 /* sleep time during pause */
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#define SLEEP1 1 /* initial sleeping time */
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#define SLEEP2 1 /* final sleeping time */
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/* Plot type */
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#define PLOT 1
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#define P_AMPLITUDE 0 /* plot amplitude of wave */
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#define P_ENERGY 1 /* plot energy of wave */
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#define P_MIXED 2 /* plot amplitude in upper half, energy in lower half */
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/* Color schemes */
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#define BLACK 1 /* background */
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#define COLOR_SCHEME 1 /* choice of color scheme */
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#define C_LUM 0 /* color scheme modifies luminosity (with slow drift of hue) */
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#define C_HUE 1 /* color scheme modifies hue */
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#define SCALE 0 /* set to 1 to adjust color scheme to variance of field */
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#define SLOPE 1.0 /* sensitivity of color on wave amplitude */
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#define ATTENUATION 0.0 /* exponential attenuation coefficient of contrast with time */
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#define E_SCALE 750.0 /* scaling factor for energy representation */
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#define COLORHUE 260 /* initial hue of water color for scheme C_LUM */
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#define COLORDRIFT 0.0 /* how much the color hue drifts during the whole simulation */
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#define LUMMEAN 0.5 /* amplitude of luminosity variation for scheme C_LUM */
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#define LUMAMP 0.3 /* amplitude of luminosity variation for scheme C_LUM */
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#define HUEMEAN 220.0 /* mean value of hue for color scheme C_HUE */
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#define HUEAMP -220.0 /* amplitude of variation of hue for color scheme C_HUE */
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/* Basic math */
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#define PI 3.141592654
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#define DPI 6.283185307
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#define PID 1.570796327
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2021-07-27 19:07:11 +02:00
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init_planar_wave(XMIN + 0.05, 0.0, phi, psi, xy_in);
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```
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2021-07-27 19:23:45 +02:00
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### 17 July 21 - Mystery billiard 8 ###
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2021-07-27 18:56:02 +02:00
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2021-07-27 19:23:45 +02:00
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**Program:** variant of `particle_billiard.c`
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2021-07-27 18:56:02 +02:00
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2021-07-27 19:23:45 +02:00
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```
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#define MOVIE 1 /* set to 1 to generate movie */
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#define WINWIDTH 720 /* window width */
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#define WINHEIGHT 720 /* window height */
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#define XMIN -1.125
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#define XMAX 1.125 /* x interval */
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#define YMIN -1.125
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#define YMAX 1.125 /* y interval for 9/16 aspect ratio */
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#define SCALING_FACTOR 1.0 /* scaling factor of drawing, needed for flower billiards, otherwise set to 1.0 */
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/* Choice of the billiard table */
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#define B_DOMAIN 20 /* choice of domain shape */
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#define D_RECTANGLE 0 /* rectangular domain */
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#define D_ELLIPSE 1 /* elliptical domain */
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#define D_STADIUM 2 /* stadium-shaped domain */
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#define D_SINAI 3 /* Sinai billiard */
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#define D_DIAMOND 4 /* diamond-shaped billiard */
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#define D_TRIANGLE 5 /* triangular billiard */
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#define D_ANNULUS 7 /* annulus */
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#define D_POLYGON 8 /* polygon */
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#define D_REULEAUX 9 /* Reuleaux and star shapes */
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#define D_FLOWER 10 /* Bunimovich flower */
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#define D_ALT_REU 11 /* alternating between star and Reuleaux */
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#define D_ANGLE 12 /* angular sector */
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#define D_LSHAPE 13 /* L-shaped billiard for conical singularity */
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#define D_GENUSN 14 /* polygon with identifies opposite sides */
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#define D_CIRCLES 20 /* several circles */
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#define NCIRCLES 4 /* number of circles */
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#define CIRCLE_PATTERN 0 /* pattern of circles */
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#define C_SQUARE 0 /* square grid of circles */
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#define LAMBDA 2.0 /* parameter controlling shape of billiard */
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#define MU 0.7 /* second parameter controlling shape of billiard */
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#define FOCI 1 /* set to 1 to draw focal points of ellipse */
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#define NPOLY 8 /* number of sides of polygon */
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#define APOLY 0.0 /* angle by which to turn polygon, in units of Pi/2 */
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#define DRAW_BILLIARD 0 /* set to 1 to draw billiard */
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#define DRAW_CONSTRUCTION_LINES 1 /* set to 1 to draw additional construction lines for billiard */
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#define PERIODIC_BC 0 /* set to 1 to enforce periodic boundary conditions when drawing particles */
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#define RESAMPLE 0 /* set to 1 if particles should be added when dispersion too large */
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#define DEBUG 0 /* draw trajectories, for debugging purposes */
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/* Simulation parameters */
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#define NPART 4000 /* number of particles */
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#define NPARTMAX 100000 /* maximal number of particles after resampling */
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#define LMAX 0.01 /* minimal segment length triggering resampling */
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#define DMIN 0.02 /* minimal distance to boundary for triggering resampling */
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#define CYCLE 1 /* set to 1 for closed curve (start in all directions) */
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#define NSTEPS 1350 /* number of frames of movie */
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#define TIME 750 /* time between movie frames, for fluidity of real-time simulation */
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#define DPHI 0.000015 /* integration step */
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#define NVID 50 /* number of iterations between images displayed on screen */
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/* Decreasing TIME accelerates the animation and the movie */
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/* For constant speed of movie, TIME*DPHI should be kept constant */
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/* However, increasing DPHI too much deterioriates quality of simulation */
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/* NVID tells how often a picture is drawn in the animation, increase it for faster anim */
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/* For a good quality movie, take for instance TIME = 400, DPHI = 0.00005, NVID = 100 */
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/* Colors and other graphical parameters */
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#define NCOLORS 15 /* number of colors */
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#define COLORSHIFT 0 /* hue of initial color */
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#define RAINBOW_COLOR 0 /* set to 1 to use different colors for all particles */
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#define FLOWER_COLOR 0 /* set to 1 to adapt initial colors to flower billiard (tracks vs core) */
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#define NSEG 100 /* number of segments of boundary */
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#define LENGTH 0.02 /* length of velocity vectors */
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#define BILLIARD_WIDTH 3 /* width of billiard */
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#define PARTICLE_WIDTH 2 /* width of particles */
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#define FRONT_WIDTH 3 /* width of wave front */
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#define BLACK 1 /* set to 1 for black background */
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#define COLOR_OUTSIDE 0 /* set to 1 for colored outside */
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#define OUTER_COLOR 270.0 /* color outside billiard */
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#define PAINT_INT 0 /* set to 1 to paint interior in other color (for polygon/Reuleaux) */
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#define PAUSE 1000 /* number of frames after which to pause */
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#define PSLEEP 1 /* sleep time during pause */
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#define SLEEP1 1 /* initial sleeping time */
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#define SLEEP2 1000 /* final sleeping time */
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#define PI 3.141592654
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#define DPI 6.283185307
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#define PID 1.570796327
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init_drop_config(0.0, 0.0, -0.1*PID, 0.1*PID, configs);
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```
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