Genetic::Algorithm::Resolver

A Ruby gem to solve optimisation problems using genetic Algorithm, inspired by the process of natural selection.

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Here is a great article on the subject: Introduction to Genetic Algorithms

Installation

Add this line to your application's Gemfile:

gem 'genetic-algorithm-resolver', git: "git@github.com:ericmatte/genetic-algorithm-resolver.git"

And then execute:

$ bundle

Or install it yourself as:

$ gem install genetic-algorithm-resolver

Usage

1. Create a genes_generator function:

def genes_generator(index = nil)
  if index.nil?
    # return a list of random genes with the chosen length of a chromosome.
  else
    # return only one random gene at the selected `index`.
  end
end

2. Create a fitness_calculator function:

def fitness_calculator(genes)
  # return the fitness score of the given list of `genes`.
end

3. Init the optimizer and parameters

ga_optimizer = Genetic::Algorithm::Optimizer.new
ga_optimizer.population_size = 200
ga_optimizer.crossover_probability = 0.7
ga_optimizer.mutation_probability = 0.5
ga_optimizer.genes_generator = method(:genes_generator)
ga_optimizer.fitness_calculator = method(:fitness_calculator)

4. execute in a loop for a given amount of generations, or until the problem is resolved:

generation = 0
last_population = nil
while generation < 500
  new_population = ga_optimizer.execute(last_population)

  best_chromosome = new_population.max_by(&:fitness)

  if problem_is_solved(best_chromosome)
    puts "Goal found!"
    break
  end

  generation += 1
  last_population = new_population
end

Example

The Shakespeare Monkey Test

Development

Setup

$ bin/setup

Test

$ rake test

Interactive prompt

Allow you to experiment with the code

$ bin/console

Debugging using VS-Code

Just start a debug session using the debug-console configuration in launch.json. This will launch a ruby console on the project, and attaches VS-Code debugger to it.

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To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/ericmatte/genetic-algorithm-resolver. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Genetic::Algorithm::Resolver project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.