examples.constraint
Class SampleFitnessFunction

java.lang.Object
  org.jgap.FitnessFunction
      examples.constraint.SampleFitnessFunction

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, ICloneable

public class SampleFitnessFunction
extends FitnessFunction

Sample fitness function for the MakeChange example.

Since:

3.6.2

See Also:

Serialized Form

Field Summary

static int

MAX_BOUND

Fields inherited from class org.jgap.FitnessFunction

DELTA, NO_FITNESS_VALUE

Constructor Summary

SampleFitnessFunction(int a_targetAmount)

Method Summary

static double	amountOfChange(IChromosome a_potentialSolution) Calculates the total amount of change (in cents) represented by the given potential solution and returns that amount.
protected double	changeDifferenceBonus(double a_maxFitness, int a_changeDifference) Bonus calculation of fitness value.
protected double	computeCoinNumberPenalty(double a_maxFitness, int a_coins) Calculates the penalty to apply to the fitness value based on the ammount of coins in the solution
double	evaluate(IChromosome a_subject) Determine the fitness of the given Chromosome instance.
static int	getNumberOfCoinsAtGene(IChromosome a_potentialSolution, int a_position) Retrieves the number of coins represented by the given potential solution at the given gene position.
static int	getTotalNumberOfCoins(IChromosome a_potentialsolution) Returns the total number of coins represented by all of the genes in the given potential solution.

Methods inherited from class org.jgap.FitnessFunction

clone, getFitnessValue, getLastComputedFitnessValue

Methods inherited from class java.lang.Object

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

Field Detail

MAX_BOUND

public static final int MAX_BOUND

See Also:

Constant Field Values

Constructor Detail

SampleFitnessFunction

public SampleFitnessFunction(int a_targetAmount)

Method Detail

evaluate

public double evaluate(IChromosome a_subject)

Determine the fitness of the given Chromosome instance. The higher the return value, the more fit the instance. This method should always return the same fitness value for two equivalent Chromosome instances.

Specified by:

evaluate in class FitnessFunction

Parameters:

a_subject - the Chromosome instance to evaluate

Returns:

positive double reflecting the fitness rating of the given Chromosome

Since:

2.0 (until 1.1: return type int)

changeDifferenceBonus

protected double changeDifferenceBonus(double a_maxFitness,
                                       int a_changeDifference)

Bonus calculation of fitness value.

Parameters:

a_maxFitness - maximum fitness value appliable

a_changeDifference - change difference in coins for the coins problem

Returns:

bonus for given change difference

Since:

2.3

computeCoinNumberPenalty

protected double computeCoinNumberPenalty(double a_maxFitness,
                                          int a_coins)

Calculates the penalty to apply to the fitness value based on the ammount of coins in the solution

Parameters:

a_maxFitness - maximum fitness value allowed

a_coins - number of coins in the solution

Returns:

penalty for the fitness value base on the number of coins

Since:

2.2

amountOfChange

public static double amountOfChange(IChromosome a_potentialSolution)

Calculates the total amount of change (in cents) represented by the given potential solution and returns that amount.

Parameters:

a_potentialSolution - the potential solution to evaluate

Returns:

The total amount of change (in cents) represented by the given solution

Since:

3.6.2

getNumberOfCoinsAtGene

public static int getNumberOfCoinsAtGene(IChromosome a_potentialSolution,
                                         int a_position)

Retrieves the number of coins represented by the given potential solution at the given gene position.

Parameters:

a_potentialSolution - the potential solution to evaluate

a_position - the gene position to evaluate

Returns:

the number of coins represented by the potential solution at the given gene position

Since:

3.6.2

getTotalNumberOfCoins

public static int getTotalNumberOfCoins(IChromosome a_potentialsolution)

Returns the total number of coins represented by all of the genes in the given potential solution.

Parameters:

a_potentialsolution - the potential solution to evaluate

Returns:

total number of coins represented by the given Chromosome

Since:

3.6.2