/*
* Encog(tm) Core v3.3 - Java Version
* http://www.heatonresearch.com/encog/
* https://github.com/encog/encog-java-core
* Copyright 2008-2014 Heaton Research, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* For more information on Heaton Research copyrights, licenses
* and trademarks visit:
* http://www.heatonresearch.com/copyright
*/
package org.encog.ml.genetic.crossover;
import java.util.Random;
import org.encog.ml.ea.genome.Genome;
import org.encog.ml.ea.opp.EvolutionaryOperator;
import org.encog.ml.ea.train.EvolutionaryAlgorithm;
import org.encog.ml.genetic.genome.ArrayGenome;
/**
* A simple cross over where genes are simply "spliced". Genes are allowed to
* repeat.
*/
public class Splice implements EvolutionaryOperator {
/**
* The cut length.
*/
private final int cutLength;
/**
* The owner.
*/
private EvolutionaryAlgorithm owner;
/**
* Create a slice crossover with the specified cut length.
* @param theCutLength The cut length.
*/
public Splice(final int theCutLength) {
this.cutLength = theCutLength;
}
/**
* {@inheritDoc}
*/
@Override
public void performOperation(Random rnd, Genome[] parents, int parentIndex,
Genome[] offspring, int offspringIndex) {
ArrayGenome mother = (ArrayGenome)parents[parentIndex];
ArrayGenome father = (ArrayGenome)parents[parentIndex+1];
ArrayGenome offspring1 = (ArrayGenome)this.owner.getPopulation().getGenomeFactory().factor();
ArrayGenome offspring2 = (ArrayGenome)this.owner.getPopulation().getGenomeFactory().factor();
offspring[offspringIndex] = offspring1;
offspring[offspringIndex+1] = offspring2;
final int geneLength = mother.size();
// the chromosome must be cut at two positions, determine them
final int cutpoint1 = (int) (rnd.nextInt(geneLength - this.cutLength));
final int cutpoint2 = cutpoint1 + this.cutLength;
// handle cut section
for (int i = 0; i < geneLength; i++) {
if (!((i < cutpoint1) || (i > cutpoint2))) {
offspring1.copy(father,i,i);
offspring2.copy(mother,i,i);
}
}
// handle outer sections
for (int i = 0; i < geneLength; i++) {
if ((i < cutpoint1) || (i > cutpoint2)) {
offspring1.copy(mother,i,i);
offspring2.copy(father,i,i);
}
}
}
/**
* @return The number of offspring produced, which is 2 for splice crossover.
*/
@Override
public int offspringProduced() {
return 2;
}
/**
* {@inheritDoc}
*/
@Override
public int parentsNeeded() {
return 2;
}
/**
* {@inheritDoc}
*/
@Override
public void init(EvolutionaryAlgorithm theOwner) {
this.owner = theOwner;
}
}