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Drools Planner optimizes automated planning by combining metaheuristic search algorithms with rule
engine powered score calculation. This is the drools-planner-core module which contains metaheuristic
algorithms.
/*
* Copyright 2010 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.drools.planner.core.localsearch.decider.acceptor.greatdeluge;
import org.drools.planner.core.localsearch.LocalSearchSolverPhaseScope;
import org.drools.planner.core.localsearch.LocalSearchStepScope;
import org.drools.planner.core.localsearch.decider.MoveScope;
import org.drools.planner.core.localsearch.decider.acceptor.AbstractAcceptor;
import org.drools.planner.core.score.Score;
/**
* TODO Under construction. Feel free to create a patch to improve this acceptor!
*/
public class GreatDelugeAcceptor extends AbstractAcceptor {
protected final double waterLevelUpperBoundRate;
protected final double waterRisingRate;
// TODO lowerboundRate when waterLevel rises on every MoveScope (not just every step) to reset waterlevel to upperbound
// protected final double waterLevelLowerBoundRate;
protected Score waterLevelScore = null;
public GreatDelugeAcceptor(double waterLevelUpperBoundRate, double waterRisingRate) {
this.waterLevelUpperBoundRate = waterLevelUpperBoundRate;
this.waterRisingRate = waterRisingRate;
}
// ************************************************************************
// Worker methods
// ************************************************************************
@Override
public void phaseStarted(LocalSearchSolverPhaseScope localSearchSolverPhaseScope) {
if (waterLevelUpperBoundRate < 1.0) {
throw new IllegalArgumentException("The greatDelugeWaterLevelUpperBoundRate (" + waterLevelUpperBoundRate
+ ") should be 1.0 or higher.");
}
if (waterRisingRate <= 0.0 || waterRisingRate >= 1.0) {
throw new IllegalArgumentException("The greatDelugeWaterRisingRate (" + waterRisingRate
+ ") should be between 0.0 and 1.0 (preferably very close to 0.0).");
}
waterLevelScore = localSearchSolverPhaseScope.getBestScore().multiply(waterLevelUpperBoundRate);
Score perfectMaximumScore = localSearchSolverPhaseScope.getScoreDefinition().getPerfectMaximumScore();
if (waterLevelScore.compareTo(perfectMaximumScore) > 0) {
throw new IllegalArgumentException("The waterLevelScore (" + waterLevelScore
+ ") should not be higher than the perfectMaximumScore(" + perfectMaximumScore + ").");
}
}
public boolean isAccepted(MoveScope moveScope) {
if (moveScope.getScore().compareTo(waterLevelScore) >= 0) {
return true;
} else {
return false;
}
}
@Override
public void stepTaken(LocalSearchStepScope localSearchStepScope) {
if (localSearchStepScope.getStepIndex() == localSearchStepScope.getLocalSearchSolverPhaseScope().getBestSolutionStepIndex()) {
// New best score
waterLevelScore = localSearchStepScope.getLocalSearchSolverPhaseScope().getBestScore().multiply(waterLevelUpperBoundRate);
} else {
Score perfectMaximumScore = localSearchStepScope.getLocalSearchSolverPhaseScope().getScoreDefinition()
.getPerfectMaximumScore();
Score waterLevelAugend = perfectMaximumScore.subtract(waterLevelScore).multiply(waterRisingRate);
waterLevelScore = waterLevelScore.add(waterLevelAugend);
// TODO maybe if waterlevel is higher than bestScore, than ...
}
}
}