Class: EvoSynth::Evolvers::SteadyStateGA

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

Overview

STEADY-STATE-GA (Weicker Page 129)

Constant Summary collapse

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

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) ⇒ SteadyStateGA

Returns a new instance of SteadyStateGA.



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# File 'lib/evosynth/evolvers/basic/steady_state_ga.rb', line 37

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

	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/steady_state_ga.rb', line 54

def best_solution
	@population.best
end

#next_generation ⇒ Object 



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# File 'lib/evosynth/evolvers/basic/steady_state_ga.rb', line 66

def next_generation
	parents = @parent_selection.select(@population, 2)

	if EvoSynth.rand < @recombination_probability
		child = @recombination.recombine(parents[0], parents[1])[0]
	else
		child = parents[1]
	end

	child = @mutation.mutate(child)
	@evaluator.calculate_and_set_fitness(child)

	@population.remove(@population.worst)
	@population.add(child)
end

#return_result ⇒ Object 



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# File 'lib/evosynth/evolvers/basic/steady_state_ga.rb', line 62

def return_result
	@population
end

#to_s ⇒ Object 



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# File 'lib/evosynth/evolvers/basic/steady_state_ga.rb', line 50

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

#worst_solution ⇒ Object 



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# File 'lib/evosynth/evolvers/basic/steady_state_ga.rb', line 58

def worst_solution
	@population.worst
end