Class: Selection::Tournament

Inherits:

Object

• Object
• Selection::Tournament

show all

Includes:

SelectMore

Defined in:

../lib/tournament.rb

Overview

Instance Attribute Summary (collapse)

• - (Object) population

  The population to select from.

• - (Object) pressure_modifier

  The probability of the selection of the best individual from the subset.

• - (Object) random

  The source of randomness, used for calling “random.rand( limit )”, defaulting to ‘Kernel’ class.

• - (Object) ranker

  The instance of the Ranking object which will be used for ranking the subset (the rank.first is the winner).

• - (Object) tournament_size

  The size of the random subset which is to be pre-selected for the tournament.

Attributes included from SelectMore

#unique_winners

Instance Method Summary (collapse)

• - (Tournament) initialize(ranker, tournament_size = 2, pressure_modifier = 1.0) constructor

  Set the instance of the Ranking object which will be used for ranking the population before the selection.

• - (Object) select_one(population = self.population)

  Select the individual from the population using the Tournament method.

Methods included from SelectMore

#select

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# File '../lib/tournament.rb', line 19

def initialize ranker, tournament_size=2, pressure_modifier=1.0
  raise "Tournament: invalid Ranking object" unless ranker.kind_of? Ranking 
  @ranker = ranker
  @tournament_size = tournament_size 
  @random = Kernel
  @pressure_modifier = pressure_modifier
end

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# File '../lib/tournament.rb', line 41

def population
  @population
end

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# File '../lib/tournament.rb', line 38

def pressure_modifier
  @pressure_modifier
end

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# File '../lib/tournament.rb', line 34

def random
  @random
end

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# File '../lib/tournament.rb', line 31

def ranker
  @ranker
end

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# File '../lib/tournament.rb', line 28

def tournament_size
  @tournament_size
end

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# File '../lib/tournament.rb', line 44

def select_one population=self.population
  raise "Tournament: empty population" if population.empty?
  raise "Tournament: tournament_size bigger than population.size" if @tournament_size > population.size 
 
  @population = population
  select_one_internal     
end