add solutions to exercises codes

README.md

@@ -26,6 +26,12 @@ presented in the book please perform the following setup steps:
 The codes for each chapter are stored in files named *chXX.jl*, where *XX* is
 chapter number.
 
+Solutions to the exercises that are presented in appendix B in
+the book are stored in *appB.jl* file. These solutions assume that they are
+executed in the same Julia session as the codes from the chapter where the
+question was posted (so that appropriate variables and functions are defined
+and appropriate packages are loaded).
+
 To work with codes from some given chapter:
 * start a fresh Julia session using the `julia --project` command in a folder
   containing the downloaded material;

appB.jl

@@ -0,0 +1,66 @@
+# Bogumił Kamiński, 2021
+
+# Codes for appendix B
+
+# Code for exercise 3.1
+
+using Statistics
+using BenchmarkTools
+aq = [10.0   8.04  10.0  9.14  10.0   7.46   8.0   6.58
+       8.0   6.95   8.0  8.14   8.0   6.77   8.0   5.76
+      13.0   7.58  13.0  8.74  13.0  12.74   8.0   7.71
+       9.0   8.81   9.0  8.77   9.0   7.11   8.0   8.84
+      11.0   8.33  11.0  9.26  11.0   7.81   8.0   8.47
+      14.0   9.96  14.0  8.1   14.0   8.84   8.0   7.04
+       6.0   7.24   6.0  6.13   6.0   6.08   8.0   5.25
+       4.0   4.26   4.0  3.1    4.0   5.39  19.0  12.50
+      12.0  10.84  12.0  9.13  12.0   8.15   8.0   5.56
+       7.0   4.82   7.0  7.26   7.0   6.42   8.0   7.91
+       5.0   5.68   5.0  4.74   5.0   5.73   8.0   6.89];
+@benchmark [cor($aq[:, i], $aq[:, i+1]) for i in 1:2:7]
+@benchmark [cor(view($aq, :, i), view($aq, :, i+1)) for i in 1:2:7]
+
+# Code for exercise 3.2
+
+function dice_distribution(dice1, dice2)
+    distribution = Dict{Int, Int}()
+    for i in dice1
+        for j in dice2
+            s = i + j
+            if haskey(distribution, s)
+                distribution[s] += 1
+            else
+                distribution[s] = 1
+            end
+        end
+    end
+    return distribution
+end
+
+function test_dice()
+    all_dice = [[1, x2, x3, x4, x5, x6]
+                for x2 in 2:11
+                for x3 in x2:11
+                for x4 in x3:11
+                for x5 in x4:11
+                for x6 in x5:11]
+
+    two_standard = dice_distribution(1:6, 1:6)
+
+    for d1 in all_dice, d2 in all_dice
+        test = dice_distribution(d1, d2)
+        if test == two_standard
+            println(d1, " ", d2)
+        end
+    end
+end
+
+test_dice()
+
+
+# Code for exercise 3.3
+
+plot(scatter(data.set1.x, data.set1.y, legend=false),
+     scatter(data.set2.x, data.set2.y, legend=false),
+     scatter(data.set3.x, data.set3.y, legend=false),
+     scatter(data.set4.x, data.set4.y, legend=false))