ec.multiobjective.nsga2

Class NSGA2Breeder

java.lang.Object

ec.Breeder

ec.simple.SimpleBreeder

ec.multiobjective.nsga2.NSGA2Breeder

All Implemented Interfaces:

Setup, Singleton, java.io.Serializable

public class NSGA2Breeder
extends SimpleBreeder

This SimpleBreeder subclass breeds a set of children from the Population, then joins the original Population with the children in a (mu+mu) fashion. An NSGA2Breeder may have multiple threads for breeding.

NSGA-II has fixed archive size (the population size), and so ignores the 'elites' declaration. However it will adhere to the 'reevaluate-elites' parameter in SimpleBreeder to determine whether to force fitness reevaluation.

See Also:

Serialized Form

Field Summary

Fields inherited from class ec.simple.SimpleBreeder

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

Constructor Summary

Constructors

Constructor and Description
NSGA2Breeder()

Method Summary

Modifier and Type	Method and Description
Population	breedPopulation(EvolutionState state) Override breedPopulation().
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

computeSubpopulationLength, numElites, shouldBreedSubpop, usingElitism

Methods inherited from class java.lang.Object

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

Constructor Detail

NSGA2Breeder

public NSGA2Breeder()

Method Detail

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)

Override breedPopulation(). We take the result from the super method in SimpleBreeder and append it to the old population. Hence, after generation 0, every subsequent call to NSGA2Evaluator.evaluatePopulation() will be passed a population of 2xoriginalPopSize individuals.

Overrides:

breedPopulation in class SimpleBreeder