edu.udo.cs.yale.operator.features.selection
Class RouletteWheel

java.lang.Object
  edu.udo.cs.yale.operator.features.selection.RouletteWheel

All Implemented Interfaces:

PopulationOperator

Direct Known Subclasses:

BoltzmannSelection

public class RouletteWheel
extends java.lang.Object
implements PopulationOperator

Selects a given fixed number of individuals by subdividing a roulette wheel in sections of size proportional to the individuals' fitness values. Optionally keep the best individual.

Version:

$Id: RouletteWheel.java,v 1.4 2006/08/03 14:39:29 ingomierswa Exp $

Author:

Simon Fischer, Ingo Mierswa

Field Summary

private boolean	keepBest
private int	popSize
private java.util.Random	random

Constructor Summary

RouletteWheel(int popSize, boolean keepBest, java.util.Random random)

Method Summary

double	filterFitness(double fitness) Subclasses may override this method and recalculate the fitness based on the given one, e.g.
void	operate(Population population) Modifies the population.
boolean	performOperation(int generation) The default implementation returns true for every generation.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

popSize

private int popSize

keepBest

private boolean keepBest

random

private java.util.Random random

Constructor Detail

RouletteWheel

public RouletteWheel(int popSize,
                     boolean keepBest,
                     java.util.Random random)

Method Detail

performOperation

public boolean performOperation(int generation)

The default implementation returns true for every generation.

Specified by:

performOperation in interface PopulationOperator

filterFitness

public double filterFitness(double fitness)

Subclasses may override this method and recalculate the fitness based on the given one, e.g. Boltzmann selection or scaled selection. The default implementation simply returns the given fitness.

operate

public void operate(Population population)

Description copied from interface: PopulationOperator

Modifies the population.

Specified by:

operate in interface PopulationOperator