Commons Math example source code file (RandomKeyMutation.java)

This example Commons Math source code file (RandomKeyMutation.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons Math tags/keywords

arraylist, chromosome, list, list, mutationpolicy, randomkey, randomkey, randomkeymutation, randomkeymutation, randomkeys, randomkeys, util

The Commons Math RandomKeyMutation.java source code

/*
 * 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;

/**
 * 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: 811685 $ $Date: 2009-09-05 13:36:48 -0400 (Sat, 05 Sep 2009) $
 */
public class RandomKeyMutation implements MutationPolicy {

    /**
     * {@inheritDoc}
     *
     * @throws IllegalArgumentException if <code>original is not a
     * {@link RandomKey} instance
     */
    public Chromosome mutate(Chromosome original) {
        if (!(original instanceof RandomKey<?>)) {
            throw MathRuntimeException.createIllegalArgumentException(
                    "RandomKeyMutation works only with RandomKeys, got " +
                    original.getClass().getSimpleName());
        }

        RandomKey<?> originalRk = (RandomKey) original;
        List<Double> repr = originalRk.getRepresentation();
        int rInd = GeneticAlgorithm.getRandomGenerator().nextInt(repr.size());

        List<Double> newRepr = new ArrayList (repr);
        newRepr.set(rInd, GeneticAlgorithm.getRandomGenerator().nextDouble());

        return originalRk.newFixedLengthChromosome(newRepr);
    }

}