genex

defmodule Genex.Tools.Benchmarks.Binary do
  @moduledoc """
  Benchmark objective functions for binary genetic algorithms.
  """

  def chuang_f1, do: :ok
  def chuang_f2, do: :ok
  def chuang_f3, do: :ok

  @doc """
  Royal Road objective function.

  Returns ```math```.

  # Parameters

    - `chromosome`: `%Chromosome{}`.
    - `order`: `Integer`.
  """
  def royal_road1(chromosome, order) do
    chromosome.genes
    |> Enum.chunk_every(order)
    |> Enum.map(&Enum.join(&1, ""))
    |> Enum.map(&String.to_integer(&1, 2))
    |> Enum.sum()
  end

  @doc """
  Royal Road 2 objective function.

  Returns ```math```.

  # Parameters

    - `chromosome`: `%Chromosome{}`.
    - `order`: `Integer`.
  """
  def royal_road2(chromosome, order),
    do: do_royal_road2(chromosome, order, floor(:math.pow(2, order)), 0)

  defp do_royal_road2(chromosome, norder, order, acc) do
    if norder >= order do
      acc
    else
      val = royal_road1(chromosome, norder)
      do_royal_road2(chromosome, order, norder * 2, acc + val)
    end
  end
end