Class: EvoSynth::Evolvers::GeneticAlgorithm

Inherits:
Object
  • Object
show all
Includes:
Evolver
Defined in:
lib/evosynth/evolvers/basic/genetic_algorithm.rb

Overview

GENETISCHER-ALGORITHMUS (Weicker Page 85)

Constant Summary collapse

DEFAULT_SELECTION = 
EvoSynth::Selections::FitnessProportionalSelection.new
DEFAULT_RECOMBINATION = 
EvoSynth::Recombinations::OnePointCrossover.new
DEFAULT_RECOMBINATION_PROBABILITY = 
0.75
DEFAULT_CHILD_FACTOR = 
0.5

Instance Attribute Summary

Attributes included from RunnableEvolver

#generations_computed

Instance Method Summary collapse

Methods included from ProfileUsingEvolver

#init_profile, #use_profile

Methods included from RunnableEvolver

#run_until, #run_until_fitness_reached, #run_until_generations_reached

Constructor Details

#initialize(profile) ⇒ GeneticAlgorithm

Returns a new instance of GeneticAlgorithm.



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# File 'lib/evosynth/evolvers/basic/genetic_algorithm.rb', line 38

def initialize(profile)
  init_profile :population, 
      :evaluator,
      :mutation,
      :parent_selection      => DEFAULT_SELECTION,
      :recombination       => DEFAULT_RECOMBINATION,
      :recombination_probability => DEFAULT_RECOMBINATION_PROBABILITY,
    :child_factor       => DEFAULT_CHILD_FACTOR

  use_profile profile

  @population.each { |individual| @evaluator.calculate_and_set_initial_fitness(individual) }
end

Instance Method Details

#best_solution ⇒ Object 



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# File 'lib/evosynth/evolvers/basic/genetic_algorithm.rb', line 56

def best_solution
  @population.best
end

#next_generation ⇒ Object 



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# File 'lib/evosynth/evolvers/basic/genetic_algorithm.rb', line 68

def next_generation
  selected_pop = @parent_selection.select(@population, @population.size * @child_factor)
  @population.clear

  selected_pop.each_index do |index_one|
    index_two = (index_one + 1) % selected_pop.size

    if EvoSynth.rand < @recombination_probability
      child_one, child_two = @recombination.recombine(selected_pop[index_one], selected_pop[index_two])
    else
      child_one = selected_pop[index_one]
      child_two = selected_pop[index_two]
    end

    @population.add(@mutation.mutate(child_one))
    @population.add(@mutation.mutate(child_two))
  end

  @population.each { |individual| @evaluator.calculate_and_set_fitness(individual) }
end

#return_result ⇒ Object 



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# File 'lib/evosynth/evolvers/basic/genetic_algorithm.rb', line 64

def return_result
  @population
end

#to_s ⇒ Object 



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# File 'lib/evosynth/evolvers/basic/genetic_algorithm.rb', line 52

def to_s
  "basic genetic algoritm <mutation: #{@mutation}, parent selection: #{@parent_selection}, recombination: #{@recombination}>"
end

#worst_solution ⇒ Object 



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# File 'lib/evosynth/evolvers/basic/genetic_algorithm.rb', line 60

def worst_solution
  @population.worst
end