/**
* Copyright (c) 1999-2014, Ecole des Mines de Nantes
* All rights reserved.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the Ecole des Mines de Nantes nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package solver.explanations.strategies;
import solver.ICause;
import solver.Solver;
import solver.exception.ContradictionException;
import solver.search.loop.lns.neighbors.ReversePropagationGuidedNeighborhood;
import solver.search.loop.monitors.IMonitorUpBranch;
import solver.search.strategy.assignments.DecisionOperator;
import solver.search.strategy.decision.Decision;
import solver.search.strategy.decision.fast.FastDecision;
import solver.variables.IntVar;
import util.objects.IntCircularQueue;
/**
* <br/>
*
* @author Charles Prud'homme
* @since 16/07/13
*/
public class RPGN4Explanation extends ReversePropagationGuidedNeighborhood implements IMonitorUpBranch {
IntCircularQueue queue;
private Decision duplicator;
private Decision last; // needed to catch up the case when a subtree is closed, and this imposes the fgmt
public RPGN4Explanation(Solver solver, IntVar[] vars, long seed, int fgmtSize, int listSize) {
super(solver, vars, seed, fgmtSize, listSize);
queue = new IntCircularQueue(vars.length);
}
@Override
public void recordSolution() {
super.recordSolution();
if (duplicator == null) {
duplicator = mSolver.getSearchLoop().getLastDecision().duplicate();
}
}
@Override
public void restrictLess() {
last = null;
super.restrictLess();
}
@Override
public void fixSomeVariables(ICause cause) throws ContradictionException {
queue.clear();
mSolver.getEnvironment().worldPush();
super.fixSomeVariables(cause);
mSolver.getEnvironment().worldPop();
while (!queue.isEmpty()) {
int id = queue.pollFirst();
FastDecision d = (FastDecision) duplicator.duplicate();
d.set(vars[id], bestSolution[id], DecisionOperator.int_eq);
last = d;
ExplanationToolbox.imposeDecisionPath(mSolver, d);
}
}
@Override
protected void impose(int id, ICause cause) throws ContradictionException {
super.impose(id, cause);
queue.addLast(id);
}
@Override
public void beforeUpBranch() {
}
@Override
public void afterUpBranch() {
// we need to catch up that case when the sub tree is closed and this imposes a fragment
if (last != null && mSolver.getSearchLoop().getLastDecision().getId() == last.getId()) {
mSolver.getSearchLoop().restart();
}
}
}