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Commons Math example source code file (

This example Commons Math source code file ( is included in the "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 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
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * 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 " +

        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);


Other Commons Math examples (source code examples)

Here is a short list of links related to this Commons Math source code file:

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