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Diffstat (limited to 'src/main/java/org/apache/commons/math/genetics/RandomKeyMutation.java')
-rw-r--r-- | src/main/java/org/apache/commons/math/genetics/RandomKeyMutation.java | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math/genetics/RandomKeyMutation.java b/src/main/java/org/apache/commons/math/genetics/RandomKeyMutation.java new file mode 100644 index 0000000..792eef2 --- /dev/null +++ b/src/main/java/org/apache/commons/math/genetics/RandomKeyMutation.java @@ -0,0 +1,57 @@ +/* + * 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; + +import org.apache.commons.math.MathRuntimeException; +import org.apache.commons.math.exception.util.LocalizedFormats; + +/** + * Mutation operator for {@link RandomKey}s. Changes a randomly chosen element + * of the array representation to a random value uniformly distributed in [0,1]. + * + * @since 2.0 + * @version $Revision: 983921 $ $Date: 2010-08-10 12:46:06 +0200 (mar. 10 août 2010) $ + */ +public class RandomKeyMutation implements MutationPolicy { + + /** + * {@inheritDoc} + * + * @throws IllegalArgumentException if <code>original</code> is not a + * {@link RandomKey} instance + */ + public Chromosome mutate(Chromosome original) { + if (!(original instanceof RandomKey<?>)) { + throw MathRuntimeException.createIllegalArgumentException( + LocalizedFormats.RANDOMKEY_MUTATION_WRONG_CLASS, + original.getClass().getSimpleName()); + } + + RandomKey<?> originalRk = (RandomKey<?>) original; + List<Double> repr = originalRk.getRepresentation(); + int rInd = GeneticAlgorithm.getRandomGenerator().nextInt(repr.size()); + + List<Double> newRepr = new ArrayList<Double> (repr); + newRepr.set(rInd, GeneticAlgorithm.getRandomGenerator().nextDouble()); + + return originalRk.newFixedLengthChromosome(newRepr); + } + +} |