/*
* Copyright 2014 JBoss Inc
*
* Licensed 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.optaplanner.core.impl.localsearch.decider.forager.finalist;
import org.optaplanner.core.api.score.Score;
import org.optaplanner.core.impl.localsearch.scope.LocalSearchMoveScope;
import org.optaplanner.core.impl.localsearch.scope.LocalSearchPhaseScope;
import org.optaplanner.core.impl.localsearch.scope.LocalSearchStepScope;
/**
* Strategic oscillation, works well with Tabu search.
* @see FinalistPodium
*/
public class StrategicOscillationByLevelFinalistPodium extends AbstractFinalistPodium {
protected final boolean referenceBestScoreInsteadOfLastStepScore;
protected Number[] referenceLevelNumbers;
protected Score finalistScore;
protected Number[] finalistLevelNumbers;
public StrategicOscillationByLevelFinalistPodium(boolean referenceBestScoreInsteadOfLastStepScore) {
this.referenceBestScoreInsteadOfLastStepScore = referenceBestScoreInsteadOfLastStepScore;
}
@Override
public void stepStarted(LocalSearchStepScope stepScope) {
super.stepStarted(stepScope);
referenceLevelNumbers = referenceBestScoreInsteadOfLastStepScore
? stepScope.getPhaseScope().getBestScore().toLevelNumbers()
: stepScope.getPhaseScope().getLastCompletedStepScope().getScore().toLevelNumbers();
finalistScore = null;
finalistLevelNumbers = null;
}
public void addMove(LocalSearchMoveScope moveScope) {
boolean accepted = moveScope.getAccepted();
if (finalistIsAccepted && !accepted) {
return;
}
if (accepted && !finalistIsAccepted) {
finalistIsAccepted = true;
finalistScore = null;
finalistLevelNumbers = null;
}
Score moveScore = moveScope.getScore();
Number[] moveLevelNumbers = moveScore.toLevelNumbers();
int comparison = doComparison(moveScore, moveLevelNumbers);
if (comparison > 0) {
finalistScore = moveScore;
finalistLevelNumbers = moveLevelNumbers;
finalistList.clear();
finalistList.add(moveScope);
} else if (comparison == 0) {
finalistList.add(moveScope);
}
}
private int doComparison(Score moveScore, Number[] moveLevelNumbers) {
if (finalistScore == null) {
return 1;
}
for (int i = 0; i < referenceLevelNumbers.length; i++) {
boolean moveIsHigher = ((Comparable) moveLevelNumbers[i]).compareTo(referenceLevelNumbers[i]) > 0;
boolean finalistIsHigher = ((Comparable) finalistLevelNumbers[i]).compareTo(referenceLevelNumbers[i]) > 0;
if (moveIsHigher) {
if (finalistIsHigher) {
break;
} else {
return 1;
}
} else if (finalistIsHigher) {
return -1;
}
}
return moveScore.compareTo(finalistScore);
}
@Override
public void phaseEnded(LocalSearchPhaseScope phaseScope) {
super.phaseEnded(phaseScope);
referenceLevelNumbers = null;
finalistScore = null;
finalistLevelNumbers = null;
}
}