org.moeaframework.algorithm
Class PESA2

java.lang.Object
  org.moeaframework.algorithm.AbstractAlgorithm
      org.moeaframework.algorithm.AbstractEvolutionaryAlgorithm
          org.moeaframework.algorithm.PESA2

All Implemented Interfaces:

Algorithm, EvolutionaryAlgorithm

public class PESA2
extends AbstractEvolutionaryAlgorithm

Implementation of the Pareto Envelope-based Selection Algorithm (PESA2).

References:

1. Corne, D. W., N. R. Jerram, J. D. Knowles, and M. J. Oates (2001). PESA-II: Region-based Selection in Evolutionary Multiobjective Optimization. Proceedings of the Genetic and Evolutionary Computation Conference (GECCO 2001), pp. 283-290.
2. Corne, D. W., J. D. Knowles, and M. J. Oates (2000). The Pareto Envelope-based Selection Algorithm for Multiobjective Optimization. Parallel Problem Solving from Nature PPSN VI, pp. 839-848.

Nested Class Summary

class

PESA2.RegionBasedSelection Region-based selection.

Field Summary

protected Map<Integer,List<Solution>>	gridMap A mapping from grid index to the solutions occupying that grid index.
protected Selection	selection The selection operator.
protected Variation	variation The variation operator.

Fields inherited from class org.moeaframework.algorithm.AbstractEvolutionaryAlgorithm

archive, initialization, population

Fields inherited from class org.moeaframework.algorithm.AbstractAlgorithm

initialized, numberOfEvaluations, problem, terminated

Constructor Summary

PESA2(Problem problem, Variation variation, Initialization initialization, int bisections, int archiveSize)

Method Summary

protected Map<Integer,List<Solution>>	createGridMap() Returns a mapping from grid index to the solutions occupying that grid index.
AdaptiveGridArchive	getArchive() Returns the current non-dominated archive of the best solutions generated by this evolutionary algorithm, or null if no archive is used.
protected void	iterate() Performs one iteration of the algorithm.

Methods inherited from class org.moeaframework.algorithm.AbstractEvolutionaryAlgorithm

getPopulation, getResult, getState, initialize, setState

Methods inherited from class org.moeaframework.algorithm.AbstractAlgorithm

evaluate, evaluateAll, evaluateAll, finalize, getNumberOfEvaluations, getProblem, isInitialized, isTerminated, step, terminate

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.moeaframework.core.Algorithm

evaluate, getNumberOfEvaluations, getProblem, isTerminated, step, terminate

Field Detail

selection

protected final Selection selection

The selection operator.

variation

protected final Variation variation

The variation operator.

gridMap

protected Map<Integer,List<Solution>> gridMap

A mapping from grid index to the solutions occupying that grid index. This enables PESA2's region-based selection.

Constructor Detail

PESA2

public PESA2(Problem problem,
             Variation variation,
             Initialization initialization,
             int bisections,
             int archiveSize)

Method Detail

getArchive

public AdaptiveGridArchive getArchive()

Description copied from interface: EvolutionaryAlgorithm

Returns the current non-dominated archive of the best solutions generated by this evolutionary algorithm, or null if no archive is used.

Specified by:

getArchive in interface EvolutionaryAlgorithm

Overrides:

getArchive in class AbstractEvolutionaryAlgorithm

Returns:

the current non-dominated archive of the best solutions generated by this evolutionary algorithm, or null if no archive is used

iterate

protected void iterate()

Description copied from class: AbstractAlgorithm

Performs one iteration of the algorithm. This method should be overridden by implementations to perform each logical iteration of the algorithm.

Specified by:

iterate in class AbstractAlgorithm

createGridMap

protected Map<Integer,List<Solution>> createGridMap()

Returns a mapping from grid index to the solutions occupying that grid index. The key is the grid index, and the value is the list of solutions occupyign that index.

Returns:

a mapping from grid index to the solutions occupying that grid index