Initial commit

.formatter.exs

@@ -0,0 +1,4 @@
+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

.gitignore

@@ -0,0 +1,26 @@
+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+genetic-*.tar
+
+# Temporary files, for example, from tests.
+/tmp/

README.md

@@ -0,0 +1,21 @@
+# Genetic
+
+**TODO: Add description**
+
+## Installation
+
+If [available in Hex](https://hex.pm/docs/publish), the package can be installed
+by adding `genetic` to your list of dependencies in `mix.exs`:
+
+```elixir
+def deps do
+  [
+    {:genetic, "~> 0.1.0"}
+  ]
+end
+```
+
+Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
+and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
+be found at <https://hexdocs.pm/genetic>.
+

lib/genetic.ex

@@ -0,0 +1,77 @@
+defmodule Genetic do
+    alias Types.Chromosome
+
+    def initialize(genotype, opts \\ []) do
+        population_size = Keyword.get(opts, :population_size, 100)
+        for _ <- 1..population_size, do: genotype.()
+    end
+
+    def evaluate(population, fitness_function, opts \\ []) do
+        population
+        |> Enum.map(
+            fn chromosome ->
+                fitness = fitness_function.(chromosome)
+                age = chromosome.age + 1
+                %Chromosome{chromosome | fitness: fitness, age: age}
+            end
+        )
+        |> Enum.sort_by(& &1.fitness, &>=/2)
+    end
+
+    def select(population, opts \\ []) do
+        population
+        |> Enum.chunk_every(2)
+        |> Enum.map(&List.to_tuple(&1))
+    end
+
+    def crossover(population, opts \\ []) do
+        population
+        |> Enum.reduce([],
+            fn {p1, p2}, acc ->
+                cx_point = :rand.uniform(length(p1.genes))
+                {{h1,t1},{h2,t2}} =
+                    {Enum.split(p1.genes, cx_point),
+                    Enum.split(p2.genes, cx_point)}
+                {c1,c2} = {%Chromosome{p1 | genes: h1 ++ t2}, %Chromosome{p2 | genes: h2 ++ t1} }
+                [c1,c2 | acc]
+            end
+        )
+    end
+
+    def mutation(population, opts \\ []) do 
+        population
+        |> Enum.map(
+            fn chromosome ->
+                if :rand.uniform() < 0.05 do
+                    %Chromosome{chromosome | genes: Enum.shuffle(chromosome)}
+                else
+                    chromosome
+                end
+            end
+        )
+    end
+
+    def run(problem, opts \\ []) do
+        population = initialize(&problem.genotype/0)
+        population 
+        |> evolve(problem, opts)
+    end
+
+    def evolve(population, problem, opts \\ []) do
+        population = evaluate(population, &problem.fitness_function/1, opts)
+        best = hd(population)
+        IO.write("\rCurrent Best: #{best.fitness}")
+        if problem.terminate?(population) do
+            best
+        else
+            population
+            |> select(opts)
+            |> crossover(opts)
+            |> mutation(opts)
+            |> evolve(problem, opts)
+        end
+
+
+    end
+
+end

lib/types/chromosome.ex

@@ -0,0 +1,12 @@
+defmodule Types.Chromosome do
+    @type t :: %__MODULE__ {
+        genes: Enum.t,
+        size: integer(),
+        fitness: number(),
+        age: integer()
+    }
+
+
+    @enforce_keys :genes
+    defstruct [:genes, size: 0, fitness: 0, age: 0]
+end

mix.exs

@@ -0,0 +1,28 @@
+defmodule Genetic.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :genetic,
+      version: "0.1.0",
+      elixir: "~> 1.13",
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      extra_applications: [:logger]
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      # {:dep_from_hexpm, "~> 0.3.0"},
+      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+    ]
+  end
+end

problem.ex

@@ -0,0 +1,9 @@
+defmodule Problem do
+    alias Types.Chromosome
+
+    @callback genotype :: Chromosome.t
+
+    @callback fitness_function(Chromosome.t) :: number()
+
+    @callback terminate?(Enum.t) :: boolean()
+end

scripts/one_max.exs

@@ -0,0 +1,23 @@
+genotype = fn -> for _ <- 1..1000, do: Enum.random(0..1) end
+
+fitness_function = fn chromosome -> Enum.sum(chromosome) end
+max_fitness = 1000
+
+defmodule OneMax do
+    @behaviour Problem
+
+    @impl Problem
+    def genotype() do
+        for _ <- 1..1000, do: Enum.random(0..
+    end
+    
+    @impl Problem
+    def fitness_function(chromosome) do
+        Enum.sum(chromosome.genes)
+    end
+end
+ 
+soln = Genetic.run(fitness_function, genotype, max_fitness)
+
+IO.write("\n")
+IO.inspect(soln)

test/genetic_test.exs

@@ -0,0 +1,8 @@
+defmodule GeneticTest do
+  use ExUnit.Case
+  doctest Genetic
+
+  test "greets the world" do
+    assert Genetic.hello() == :world
+  end
+end

test/test_helper.exs

@@ -0,0 +1 @@
+ExUnit.start()