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 * The ASF licenses this file to You under the Apache License, Version 2.0
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 *      http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.commons.math3.genetics;

import java.util.ArrayList;
import java.util.List;

import org.apache.commons.math3.exception.MathIllegalArgumentException;
import org.apache.commons.math3.exception.util.LocalizedFormats;

Mutation for BinaryChromosomes. Randomly changes one gene.
Since:2.0
/** * Mutation for {@link BinaryChromosome}s. Randomly changes one gene. * * @since 2.0 */
public class BinaryMutation implements MutationPolicy {
Mutate the given chromosome. Randomly changes one gene.
Params:
  • original – the original chromosome.
Throws:
Returns:the mutated chromosome.
/** * Mutate the given chromosome. Randomly changes one gene. * * @param original the original chromosome. * @return the mutated chromosome. * @throws MathIllegalArgumentException if <code>original</code> is not an instance of {@link BinaryChromosome}. */
public Chromosome mutate(Chromosome original) throws MathIllegalArgumentException { if (!(original instanceof BinaryChromosome)) { throw new MathIllegalArgumentException(LocalizedFormats.INVALID_BINARY_CHROMOSOME); } BinaryChromosome origChrom = (BinaryChromosome) original; List<Integer> newRepr = new ArrayList<Integer>(origChrom.getRepresentation()); // randomly select a gene int geneIndex = GeneticAlgorithm.getRandomGenerator().nextInt(origChrom.getLength()); // and change it newRepr.set(geneIndex, origChrom.getRepresentation().get(geneIndex) == 0 ? 1 : 0); Chromosome newChrom = origChrom.newFixedLengthChromosome(newRepr); return newChrom; } }