ruby-jgap

A Ruby DSL for Genetic Algorithms using JGAP.

The JGAP binary JAR file is packaged with this gem.

JGAP is licensed under the GNU Lesser Public license; if you would like to use this gem in commercial applications, you can choose to use the Mozilla Public License and donate 50 euros to JGAP. more details

Install

gem install ruby-jgap

or

jruby -S gem install ruby-jgap

Usage

require 'java'
require 'ruby-jgap'

# subclass JGAP::Problem
class MakeChangeProblem < JGAP::Problem

  population_size 500

  # define our solution chromosome
  chromosome do
    integer :quarters, min: 0, max: 3
    integer :dimes,    min: 0, max: 2
    integer :nickels,  min: 0, max: 1
    integer :pennies,  min: 0, max: 4
  end

  # define our fitness function
  fitness_function do |subject|
    target = 47 # goal: 47 cents
    q = read subject, :quarters
    d = read subject, :dimes
    n = read subject, :nickels
    p = read subject, :pennies
    
    coins = q + d + n + p
    value = 25*q + 10*d + 5*n + p
    delta = (target - value).abs # how far are we from our goal?
    
    minimize(coins + 2*delta) # minimize our cost
  end


end

problem = MakeChangeProblem.new
problem.run(100) # 100 generations
problem.print_best

This outputs (probably):

quarters: 1
dimes: 2
nickels: 0
pennies: 2

Adapted from the Getting Started page on JGAP's site.