org.jgap
Class FitnessFunction

java.lang.Object
  org.jgap.FitnessFunction

All Implemented Interfaces:

java.io.Serializable

public abstract class FitnessFunction

extends java.lang.Object

implements java.io.Serializable

Fitness functions are used to determine how optimal a particular solution is relative to other solutions. This abstract class should be extended and the evaluate() method implemented. The fitness function is given a Chromosome to evaluate and should return a positive integer that reflects its fitness value. The higher the value, the more fit the Chromosome. The actual range of fitness values isn't important (other than the fact that they must be positive integers): it's the relative difference as a percentage that tends to determine the success or failure of a Chromosome. So in other words, two Chromosomes with respective fitness values of 1 and 100 have the same relative fitness to each other as two Chromosomes with respective fitness values of 10 and 1000 (in each case, the first is 1% as fit as the second).

Note: Two Chromosomes with equivalent sets of genes should always be assigned the same fitness value by any implementation of this interface.

Since:

1.0

Author:

Neil Rotstan, Klaus Meffert

See Also:

Serialized Form

Constructor Summary

FitnessFunction()

Method Summary

double	getFitnessValue(Chromosome a_subject) Retrieves the fitness value of the given Chromosome.
double	getNoFitnessValue()

Methods inherited from class java.lang.Object

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

Constructor Detail

FitnessFunction

public FitnessFunction()

Method Detail

getFitnessValue

public final double getFitnessValue(Chromosome a_subject)

Retrieves the fitness value of the given Chromosome. The fitness value will be a positive double.

Parameters:

a_subject - the Chromosome for which to compute and return the fitness value.

Returns:

the fitness value of the given Chromosome.

Since:

2.0 (until 1.1: return type int)

getNoFitnessValue

public double getNoFitnessValue()

Returns:

the double value that indicated that there is no fitness value assigned yet

Since:

2.0