genetic

commit 1334fb37eec2293ba065e1fc8e2009b2925a2ecb
parent 2eecb3f32236433e558c3e451bd0d5437b1a838c
Author: dracuxan <[email protected]>
Date:   Thu, 30 Apr 2026 12:11:16 +0530

new: sin(x)

Diffstat:
M
lib/toolbox/crossover.ex
 | 
33
+++++++++++++++++++++++++++++++++
A
scripts/sin.exs
 | 
99
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 132 insertions(+), 0 deletions(-)
diff --git a/lib/toolbox/crossover.ex b/lib/toolbox/crossover.ex
@@ -65,6 +65,39 @@ defmodule Toolbox.Crossover do
     }
   end
 
+  def blend(p1, p2, opts \\ []) do
+    p1_1 = Enum.at(p1.genes, 0)
+    p2_1 = Enum.at(p2.genes, 0)
+    alpha = Keyword.get(opts, :alpha, 1)
+    {min, max} = {Keyword.get(opts, :min, -10), Keyword.get(opts, :max, 10)}
+    shift = (0.1 + 0.2 * alpha) * :rand.uniform() - alpha
+    c1 = (0.1 - shift) * p1_1 + shift * p2_1
+    c2 = shift * p1_1 + (0.1 - shift) * p2_1
+
+    {
+      %Chromosome{genes: [utils_constraints(c1, min, max)], size: 1, age: 0},
+      %Chromosome{genes: [utils_constraints(c2, min, max)], size: 1, age: 0}
+    }
+  end
+
+  defp utils_constraints(p, min, max) do
+    p =
+      if p > max do
+        max
+      else
+        p
+      end
+
+    p =
+      if p < min do
+        min
+      else
+        p
+      end
+
+    p
+  end
+
   def whole_arethmetic(p1, p2, opts \\ []) do
     alpha = Keyword.get(opts, :alpha, 0.5)
 
diff --git a/scripts/sin.exs b/scripts/sin.exs
@@ -0,0 +1,99 @@
+defmodule Sin do
+  alias Types.Chromosome
+  @behaviour Problem
+
+  @impl true
+  def genotype do
+    genes = :rand.uniform(10)
+    %Chromosome{genes: [genes], size: 1}
+  end
+
+  @impl true
+  def fitness_function(chromosome) do
+    x = Enum.at(chromosome.genes, 0)
+    Math.sin(x) - 0.2 * abs(x)
+  end
+
+  @impl true
+  def terminate?(population, generation) do
+    plot_generation(population, generation)
+    generation == 10
+  end
+
+  def plot_generation(population, generation) do
+    curve =
+      Enum.map(-10..10, fn x ->
+        [x, :math.sin(x) - 0.2 * abs(x)]
+      end)
+
+    points =
+      Enum.map(population, fn c ->
+        [hd(c.genes), c.fitness]
+      end)
+
+    best = hd(population)
+    best_point = [[hd(best.genes), best.fitness]]
+
+    Gnuplot.plot(
+      [
+        [:set, :title, "Generation #{generation}"],
+        [:set, :xrange, ~c"[-10:10]"],
+        [:set, :yrange, ~c"[-3:1]"],
+        [
+          :plot,
+          "-",
+          :with,
+          :lines,
+          :lt,
+          2,
+          :title,
+          "sin(x) - 0.2|x|",
+          "-",
+          :with,
+          :points,
+          :pt,
+          7,
+          :ps,
+          1.5,
+          :lc,
+          "orange",
+          :title,
+          "Population",
+          "-",
+          :with,
+          :points,
+          :pt,
+          5,
+          :ps,
+          2,
+          :lc,
+          "green",
+          :title,
+          "Best"
+        ]
+      ],
+      [
+        curve,
+        points,
+        best_point
+      ]
+    )
+  end
+end
+
+{soln, gen} =
+  Genetic.run(
+    Sin,
+    population_size: 10,
+    selection_rate: 0.8,
+    mutation_rate: 0.1,
+    alpha: 1,
+    min: -10,
+    max: 10,
+    selection_type: &Toolbox.Selection.tournament/2,
+    crossover_type: &Toolbox.Crossover.blend/3,
+    mutation_type: &Toolbox.Mutation.gaussian/2
+  )
+
+IO.puts("\nfinal answer: #{inspect(soln)}")
+IO.puts("generations passed: #{gen}")