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* Licensed to the Apache Software Foundation (ASF) under one or more
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* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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,
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* See the License for the specific language governing permissions and
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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 BinaryChromosome
s. 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: - MathIllegalArgumentException – if
original
is not an instance of BinaryChromosome
.
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;
}
}