org.apache.commons.math3.genetics.RandomKeyMutation Maven / Gradle / Ivy
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/*
* 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 java.util.ArrayList;
import java.util.List;
import org.apache.commons.math3.exception.MathIllegalArgumentException;
import org.apache.commons.math3.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
*/
public class RandomKeyMutation implements MutationPolicy {
/**
* {@inheritDoc}
*
* @throws MathIllegalArgumentException if original 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 repr = originalRk.getRepresentation();
int rInd = GeneticAlgorithm.getRandomGenerator().nextInt(repr.size());
List newRepr = new ArrayList (repr);
newRepr.set(rInd, GeneticAlgorithm.getRandomGenerator().nextDouble());
return originalRk.newFixedLengthChromosome(newRepr);
}
}