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.simple;
017    
018    import de.kumpe.hadooptimizer.EsIndividual;
019    import de.kumpe.hadooptimizer.EsOptimizerConfiguration;
020    import de.kumpe.hadooptimizer.EvaluationResult;
021    import de.kumpe.hadooptimizer.Optimizer;
022    
023    /**
024     * A multithreaded {@link Optimizer} implementation for evolution strategies.
025     * 
026     * @see Optimizer
027     * @see ThreadedOptimizerBase
028     * 
029     * @author <a href="http://kumpe.de/christian/java">Christian Kumpe</a>
030     */
031    public class ThreadedEsOptimizer extends ThreadedOptimizerBase<EsIndividual> {
032            public ThreadedEsOptimizer(final EsOptimizerConfiguration configuration) {
033                    super(configuration);
034            }
035    
036            @Override
037            protected EsOptimizerConfiguration getConfiguration() {
038                    return (EsOptimizerConfiguration) super.getConfiguration();
039            }
040    
041            @Override
042            void processPopulation() throws Exception {
043                    // duplicate and add children to processing queue
044                    final int nrOfParents = evaluationResults.size();
045                    @SuppressWarnings("unchecked")
046                    final EvaluationResult<EsIndividual>[] parentsAsArray = (EvaluationResult<EsIndividual>[]) evaluationResults
047                                    .toArray(new EvaluationResult<?>[nrOfParents]);
048    
049                    if (!getConfiguration().isPreserveParents()) {
050                            evaluationResults.clear();
051                    }
052    
053                    resetEvaluationResultCounters(getConfiguration().getOffspring());
054    
055                    for (int i = 0; i < getConfiguration().getOffspring(); i++) {
056                            final int selectedParent = getRandomGenerator()
057                                            .nextInt(nrOfParents);
058                            individualsToProcess.add(parentsAsArray[selectedParent]
059                                            .getIndividual());
060                    }
061    
062                    waitForEvaluationResults();
063            }
064    }