| /* |
| * 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.math.genetics; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| /** |
| * Mutation for {@link BinaryChromosome}s. Randomly changes one gene. |
| * |
| * @version $Revision$ $Date$ |
| * @since 2.0 |
| */ |
| public class BinaryMutation implements MutationPolicy { |
| |
| /** |
| * Mutate the given chromosome. Randomly changes one gene. |
| * @param original the original chromosome. |
| * @return the mutated chromomsome. |
| */ |
| public Chromosome mutate(Chromosome original) { |
| if (!(original instanceof BinaryChromosome)) { |
| throw new IllegalArgumentException("Binary mutation works on BinaryChromosome only."); |
| } |
| |
| 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; |
| } |
| |
| } |