| /* |
| * 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); |
| } |
| |
| } |