/*
* Copyright 2014 Red Hat, Inc. and/or its affiliates.
*
* 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.solver.termination;
import org.optaplanner.core.impl.phase.scope.AbstractPhaseScope;
import org.optaplanner.core.impl.solver.ChildThreadType;
import org.optaplanner.core.impl.solver.scope.DefaultSolverScope;
public class UnimprovedTimeMillisSpentTermination extends AbstractTermination {
private final long unimprovedTimeMillisSpentLimit;
public UnimprovedTimeMillisSpentTermination(long unimprovedTimeMillisSpentLimit) {
this.unimprovedTimeMillisSpentLimit = unimprovedTimeMillisSpentLimit;
if (unimprovedTimeMillisSpentLimit <= 0L) {
throw new IllegalArgumentException("The unimprovedTimeMillisSpentLimit (" + unimprovedTimeMillisSpentLimit
+ ") cannot be negative.");
}
}
public long getUnimprovedTimeMillisSpentLimit() {
return unimprovedTimeMillisSpentLimit;
}
// ************************************************************************
// Terminated methods
// ************************************************************************
@Override
public boolean isSolverTerminated(DefaultSolverScope solverScope) {
long bestSolutionTimeMillis = solverScope.getBestSolutionTimeMillis();
return isTerminated(bestSolutionTimeMillis);
}
@Override
public boolean isPhaseTerminated(AbstractPhaseScope phaseScope) {
long bestSolutionTimeMillis = phaseScope.getPhaseBestSolutionTimeMillis();
return isTerminated(bestSolutionTimeMillis);
}
protected boolean isTerminated(long bestSolutionTimeMillis) {
long now = System.currentTimeMillis();
long unimprovedTimeMillisSpent = now - bestSolutionTimeMillis;
return unimprovedTimeMillisSpent >= unimprovedTimeMillisSpentLimit;
}
// ************************************************************************
// Time gradient methods
// ************************************************************************
@Override
public double calculateSolverTimeGradient(DefaultSolverScope solverScope) {
long bestSolutionTimeMillis = solverScope.getBestSolutionTimeMillis();
return calculateTimeGradient(bestSolutionTimeMillis);
}
@Override
public double calculatePhaseTimeGradient(AbstractPhaseScope phaseScope) {
long bestSolutionTimeMillis = phaseScope.getPhaseBestSolutionTimeMillis();
return calculateTimeGradient(bestSolutionTimeMillis);
}
protected double calculateTimeGradient(long bestSolutionTimeMillis) {
long now = System.currentTimeMillis();
long unimprovedTimeMillisSpent = now - bestSolutionTimeMillis;
double timeGradient = ((double) unimprovedTimeMillisSpent) / ((double) unimprovedTimeMillisSpentLimit);
return Math.min(timeGradient, 1.0);
}
// ************************************************************************
// Other methods
// ************************************************************************
@Override
public UnimprovedTimeMillisSpentTermination createChildThreadTermination(
DefaultSolverScope solverScope, ChildThreadType childThreadType) {
return new UnimprovedTimeMillisSpentTermination(unimprovedTimeMillisSpentLimit);
}
@Override
public String toString() {
return "UnimprovedTimeMillisSpent(" + unimprovedTimeMillisSpentLimit + ")";
}
}