org.artoflife.gp.population
Class DecayingMinFitnessGenerationalPopulation

java.lang.Object
  |
  +--org.artoflife.gp.Population
        |
        +--org.artoflife.gp.population.GenerationalPopulation
              |
              +--org.artoflife.gp.population.MinFitnessGenerationalPopulation
                    |
                    +--org.artoflife.gp.population.DecayingMinFitnessGenerationalPopulation

All Implemented Interfaces:

java.io.Serializable

public class DecayingMinFitnessGenerationalPopulation

extends MinFitnessGenerationalPopulation

A MinFitnessGenerationalPopulation that decreases the fitness of all individuals after a step. Fitter individuals decay less quickly than less fit ones.

Author:

Steve Meyfroidt

See Also:

Serialized Form

Field Summary

Fields inherited from class org.artoflife.gp.population.MinFitnessGenerationalPopulation

maxCull, minFitness

Fields inherited from class org.artoflife.gp.population.GenerationalPopulation

FITNESS_COMPARATOR, individualClass, populationSize, selectorClass

Fields inherited from class org.artoflife.gp.Population

individuals

Constructor Summary

DecayingMinFitnessGenerationalPopulation(int populationSize, java.lang.Class individualClass, int maxCull, float minFitness, java.util.SortedMap reproducers, float maxFitness, float decayScale)

Method Summary

Individual	breedNewIndividual(Selector selector) Override to allow plug-point for manipulating fitness of newly created individuals, useful for the Generator GUI where new individuals are all assigned a fixed fitness just below the threshold for "protected" parents whose fitness does not decay.
float	getNewFitness()
void	newGeneration() Override to reduce fitness of all individuals after the step.
void	setNewFitness(float newFitness)

Methods inherited from class org.artoflife.gp.population.MinFitnessGenerationalPopulation

cullOneWeakest, cullWeakest, cullWeakest

Methods inherited from class org.artoflife.gp.population.GenerationalPopulation

breed, getIdealPopulationSize, makeSelector, newIndividual, setIdealPopulationSize, setSelectorClass

Methods inherited from class org.artoflife.gp.Population

addIndividual, addNewIndividuals, addPopulationListener, firePopulationEvent, getIndividuals, getReproducers, removeIndividual, removePopulationListener

Methods inherited from class java.lang.Object

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

Constructor Detail

DecayingMinFitnessGenerationalPopulation

public DecayingMinFitnessGenerationalPopulation(int populationSize,
                                                java.lang.Class individualClass,
                                                int maxCull,
                                                float minFitness,
                                                java.util.SortedMap reproducers,
                                                float maxFitness,
                                                float decayScale)

Parameters:

maxFitness - the max fitness at which individuals don't decay

decayScale - a fitness is reduced by (maxFitness-fitness)*decayScale

Method Detail

newGeneration

public void newGeneration()

Override to reduce fitness of all individuals after the step.

Overrides:

newGeneration in class Population

breedNewIndividual

public Individual breedNewIndividual(Selector selector)
                              throws IncompatibleGenotypeException

Override to allow plug-point for manipulating fitness of newly created individuals, useful for the Generator GUI where new individuals are all assigned a fixed fitness just below the threshold for "protected" parents whose fitness does not decay.

Overrides:

breedNewIndividual in class Population

Parameters:

selector - to use for selection of parents of the breeding

Returns:

a new Individual, never null

Throws:

IncompatibleGenotypeException - when breeding between individuals with incompatible genotypes

See Also:

Population.breedNewIndividual(org.artoflife.gp.Selector)

getNewFitness

public float getNewFitness()

Returns:

float

setNewFitness

public void setNewFitness(float newFitness)

Parameters:

newFitness - The newFitness to set