org.encog.ml.prg.opp
Class SubtreeMutation

java.lang.Object
  org.encog.ml.prg.opp.SubtreeMutation

All Implemented Interfaces:

EvolutionaryOperator

public class SubtreeMutation
extends Object
implements EvolutionaryOperator

Perform a type-safe subtree mutation. The mutation point is chosen randomly, but the new tree will be generated with compatible types to the parent.

Constructor Summary

SubtreeMutation(EncogProgramContext theContext, int theMaxDepth)
Construct the subtree mutation object.

Method Summary

PrgGenerator	getGenerator()
void	init(EvolutionaryAlgorithm theOwner) Called to setup the evolutionary operator.
int	offspringProduced()
int	parentsNeeded()
void	performOperation(Random rnd, Genome[] parents, int parentIndex, Genome[] offspring, int offspringIndex) Perform the evolutionary operation.
void	setGenerator(PrgGenerator generator) Set the random tree generator to use.

Methods inherited from class java.lang.Object

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

Constructor Detail

SubtreeMutation

public SubtreeMutation(EncogProgramContext theContext,
                       int theMaxDepth)

Construct the subtree mutation object.

Parameters:

theContext - The program context.

theMaxDepth - The maximum depth.

Method Detail

getGenerator

public PrgGenerator getGenerator()

Returns:

The random tree generator to use.

init

public void init(EvolutionaryAlgorithm theOwner)

Called to setup the evolutionary operator.

Specified by:

init in interface EvolutionaryOperator

Parameters:

theOwner - The evolutionary algorithm used with this operator.

offspringProduced

public int offspringProduced()

Specified by:

offspringProduced in interface EvolutionaryOperator

Returns:

Returns the number of offspring produced. In this case, one.

parentsNeeded

public int parentsNeeded()

Specified by:

parentsNeeded in interface EvolutionaryOperator

Returns:

Returns the number of parents needed. In this case, one.

performOperation

public void performOperation(Random rnd,
                             Genome[] parents,
                             int parentIndex,
                             Genome[] offspring,
                             int offspringIndex)

Perform the evolutionary operation.

Specified by:

performOperation in interface EvolutionaryOperator

Parameters:

rnd - A random number generator.

parents - The parents.

parentIndex - The index into the parents array.

offspring - The offspring.

offspringIndex - An index into the offspring array.

setGenerator

public void setGenerator(PrgGenerator generator)

Set the random tree generator to use.

Parameters:

generator - The random tree generator.