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

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

All Implemented Interfaces:

PopulationOperator

public class BoltzmannSelection
extends RouletteWheel

Like RouletteWheel this population operator selects a given fixed number of individuals by subdividing a roulette wheel in sections of size proportional to the individuals' fitness values. The fitness values are filtered according to the Boltzmann theorem.

Version:

$Id: BoltzmannSelection.java,v 1.1 2006/04/14 07:47:17 ingomierswa Exp $

Author:

Ingo Mierswa

Field Summary

private double	delta
private double	temperature

Constructor Summary

BoltzmannSelection(int popSize, double temperature, int maxGenerations, boolean dynamic, boolean keepBest, java.util.Random random)

Method Summary

double	filterFitness(double fitness) Returns a fitness based on the Boltzmann theorem, i.e.
void	operate(Population population) Applies the method from the superclass and decreases the temperature in the adaptive case.

Methods inherited from class edu.udo.cs.yale.operator.features.selection.RouletteWheel

performOperation

Methods inherited from class java.lang.Object

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

Field Detail

temperature

private double temperature

delta

private double delta

Constructor Detail

BoltzmannSelection

public BoltzmannSelection(int popSize,
                          double temperature,
                          int maxGenerations,
                          boolean dynamic,
                          boolean keepBest,
                          java.util.Random random)

Method Detail

filterFitness

public double filterFitness(double fitness)

Returns a fitness based on the Boltzmann theorem, i.e. exp(fitness/temperature). Like for simulated annealing the temperature should decrease over time.

Overrides:

filterFitness in class RouletteWheel

operate

public void operate(Population population)

Applies the method from the superclass and decreases the temperature in the adaptive case.

Specified by:

operate in interface PopulationOperator

Overrides:

operate in class RouletteWheel