001    /*
002     * Copyright 2011 Christian Kumpe http://kumpe.de/christian/java
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     *     http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    package de.kumpe.hadooptimizer.impl;
017    
018    import org.apache.commons.logging.Log;
019    import org.apache.commons.logging.LogFactory;
020    
021    import de.kumpe.hadooptimizer.Mutator;
022    
023    /**
024     * Mutates a {@code double} array by adding gaussian random numbers. The passed
025     * array will not be modified, a new array will be returned.
026     * 
027     * @author <a href="http://kumpe.de/christian/java">Christian Kumpe</a>
028     */
029    public final class GaussianMutator extends GaussionMutatorBase implements
030                    Mutator<double[]> {
031            private static final long serialVersionUID = 1L;
032            private static final Log log = LogFactory.getLog(GaussianMutator.class);
033    
034            public GaussianMutator() {
035                    this(1);
036            }
037    
038            public GaussianMutator(final double standardDeviation) {
039                    super(standardDeviation);
040                    if (log.isDebugEnabled()) {
041                            log.debug("Constructing new GaussianMutator with a standard deviation of "
042                                            + standardDeviation);
043                    }
044            }
045    
046            @Override
047            public double[] mutate(final double[] individual) {
048                    return mutate(individual, standardDeviation);
049            }
050    }