diff options
Diffstat (limited to 'src/main/java/org/apache/commons/math3/genetics/RandomKeyMutation.java')
-rw-r--r-- | src/main/java/org/apache/commons/math3/genetics/RandomKeyMutation.java | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math3/genetics/RandomKeyMutation.java b/src/main/java/org/apache/commons/math3/genetics/RandomKeyMutation.java new file mode 100644 index 0000000..6d1512a --- /dev/null +++ b/src/main/java/org/apache/commons/math3/genetics/RandomKeyMutation.java @@ -0,0 +1,55 @@ +/* + * 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.math3.genetics; + +import org.apache.commons.math3.exception.MathIllegalArgumentException; +import org.apache.commons.math3.exception.util.LocalizedFormats; + +import java.util.ArrayList; +import java.util.List; + +/** + * 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 + */ +public class RandomKeyMutation implements MutationPolicy { + + /** + * {@inheritDoc} + * + * @throws MathIllegalArgumentException if <code>original</code> is not a {@link RandomKey} + * instance + */ + public Chromosome mutate(final Chromosome original) throws MathIllegalArgumentException { + if (!(original instanceof RandomKey<?>)) { + throw new MathIllegalArgumentException( + 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); + } +} |