Package ec.multiobjective.spea2

Class SPEA2Breeder

java.lang.Object

ec.Breeder

ec.simple.SimpleBreeder

ec.multiobjective.spea2.SPEA2Breeder

All Implemented Interfaces:

Setup, Singleton, Serializable

public class SPEA2Breeder
extends SimpleBreeder

This subclass of SimpleBreeder overrides the loadElites method to build an archive in the top elites[subpopnum] of each subpopulation. It computes the sparsity metric, then constructs the archive.

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	SPEA2Breeder.BreedingState	We use a state variable to make sure that the archive isn't built twice in a row.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	P_K
static final String	P_NORMALIZE

Fields inherited from class ec.simple.SimpleBreeder

backupPopulation, clonePipelineAndPopulation, elite, eliteFrac, newIndividuals, P_CLONE_PIPELINE_AND_POPULATION, P_ELITE, P_ELITE_FRAC, P_REEVALUATE_ELITES, P_SEQUENTIAL_BREEDING, pool, reevaluateElites

Fields inherited from class ec.Breeder

sequentialBreeding

Constructor Summary

Constructors

Constructor	Description
SPEA2Breeder()

Method Summary

Modifier and Type	Method	Description
Population	breedPopulation(EvolutionState state)	Use super's breeding, but also set our local state to record that breeding is complete.
double[]	calculateDistancesFromIndividual(Individual ind, ArrayList<Individual> inds)
protected void	loadElites(EvolutionState state, Population newpop)	Extract the elite individuals from the current population and both place in newpop and replace the current population with the archive.
int	numElites(EvolutionState state, int subpopulation)	Return the number of individuals that we aim to see in the elitist archive.
void	postProcess(EvolutionState state)	A hook to do final modifications as necessary to the population after breeding has concluded.
void	setup(EvolutionState state, Parameter base)	Sets up the object by reading it from the parameters stored in state, built off of the parameter base base.

Methods inherited from class ec.simple.SimpleBreeder

breedPopChunk, breedPopChunkProduce, nextSubpopulationSize, shouldBreedSubpop, unmarkElitesEvaluated, usingElitism

Methods inherited from class java.lang.Object

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

Field Details

P_K

public static final String P_K

See Also:

• Constant Field Values

P_NORMALIZE

public static final String P_NORMALIZE

See Also:

• Constant Field Values

Constructor Details

SPEA2Breeder

public SPEA2Breeder()

Method Details

setup

public void setup(EvolutionState state,
 Parameter base)

Description copied from interface: Setup

Sets up the object by reading it from the parameters stored in state, built off of the parameter base base. If an ancestor implements this method, be sure to call super.setup(state,base); before you do anything else.

Specified by:

setup in interface Setup

Overrides:

setup in class SimpleBreeder

breedPopulation

public Population breedPopulation(EvolutionState state)

Use super's breeding, but also set our local state to record that breeding is complete.

Overrides:

breedPopulation in class SimpleBreeder

numElites

public int numElites(EvolutionState state,
 int subpopulation)

Return the number of individuals that we aim to see in the elitist archive. This can only be called after loadArchive() and before breedPopulation().

Overrides:

numElites in class SimpleBreeder

loadElites

protected void loadElites(EvolutionState state,
 Population newpop)

Extract the elite individuals from the current population and both place in newpop and replace the current population with the archive. We place the elites straight into the current population because breeding is the next thing that happens right after loadElites() is called, and SPEA breeds children from the elitist archive.

Overrides:

loadElites in class SimpleBreeder

postProcess

public void postProcess(EvolutionState state)

Description copied from class: SimpleBreeder

A hook to do final modifications as necessary to the population after breeding has concluded. By default this does nothing, but multiobjective breeders, which temporarily replace the old population while it's being breeded, may use this to put the popuplation back again just in case statistics needs it.

Overrides:

postProcess in class SimpleBreeder

calculateDistancesFromIndividual

public double[] calculateDistancesFromIndividual(Individual ind,
 ArrayList<Individual> inds)