BinaryMutation.java
- /*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * 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,
- * 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.
- */
- package org.apache.commons.math4.legacy.genetics;
- import java.util.ArrayList;
- import java.util.List;
- import org.apache.commons.math4.legacy.exception.MathIllegalArgumentException;
- import org.apache.commons.math4.legacy.exception.util.LocalizedFormats;
- /**
- * 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.
- *
- * @param original the original chromosome.
- * @return the mutated chromosome.
- * @throws MathIllegalArgumentException if <code>original</code> is not an instance of {@link BinaryChromosome}.
- */
- @Override
- 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<>(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);
- return origChrom.newFixedLengthChromosome(newRepr);
- }
- }