org.chocosolver.graphsolver.cstrs.channeling.edges.PropSuccIntsChannel1 Maven / Gradle / Ivy

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A graph module for Choco Solver.
There is a newer version: 4.2.2
/**
 *  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 org.chocosolver.graphsolver.cstrs.channeling.edges;

import org.chocosolver.graphsolver.variables.GraphEventType;
import org.chocosolver.graphsolver.variables.IDirectedGraphVar;
import org.chocosolver.graphsolver.variables.delta.IGraphDeltaMonitor;
import org.chocosolver.solver.constraints.Propagator;
import org.chocosolver.solver.constraints.PropagatorPriority;
import org.chocosolver.solver.exception.ContradictionException;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.util.ESat;
import org.chocosolver.util.objects.setDataStructures.ISet;
import org.chocosolver.util.procedure.PairProcedure;

/**
 * @author Jean-Guillaume Fages
 */
public class PropSuccIntsChannel1 extends Propagator {

	//***********************************************************************************
	// VARIABLES
	//***********************************************************************************

	private int n;
	private IntVar[] succs;
	private IGraphDeltaMonitor gdm;
	private IDirectedGraphVar g;
	private PairProcedure arcForced, arcRemoved;

	//***********************************************************************************
	// CONSTRUCTORS
	//***********************************************************************************

	public PropSuccIntsChannel1(final IntVar[] succs, IDirectedGraphVar gV) {
		super(new IDirectedGraphVar[]{gV}, PropagatorPriority.LINEAR, true);
		this.succs = succs;
		n = succs.length;
		this.g = gV;
		assert (n == g.getNbMaxNodes());
		gdm = g.monitorDelta(this);
		for(int i=0;i succs[i].instantiateTo(j, this);
		arcRemoved = (i, j) -> succs[i].removeValue(j, this);
	}

	//***********************************************************************************
	// METHODS
	//***********************************************************************************

	@Override
	public void propagate(int evtmask) throws ContradictionException {
		for (int i = 0; i < n; i++) {
			ISet tmp = g.getMandSuccOrNeighOf(i);
			for (int j : tmp) {
				succs[i].instantiateTo(j, this);
			}
			for (int j=succs[i].getLB(); j<=succs[i].getUB(); j=succs[i].nextValue(j)) {
				if (!g.getPotSuccOrNeighOf(i).contains(j)) {
					succs[i].removeValue(j, this);
				}
			}
		}
		gdm.unfreeze();
	}

	@Override
	public void propagate(int idxVarInProp, int mask) throws ContradictionException {
		gdm.freeze();
		gdm.forEachArc(arcForced, GraphEventType.ADD_ARC);
		gdm.forEachArc(arcRemoved, GraphEventType.REMOVE_ARC);
		gdm.unfreeze();
	}

	@Override
	public ESat isEntailed() {
		for (int i = 0; i < n; i++) {
			if(succs[i].isInstantiated()){
				if (!g.getPotSuccOrNeighOf(i).contains(succs[i].getValue())) {
					return ESat.FALSE;
				}
			}
			ISet tmp = g.getMandSuccOrNeighOf(i);
			for (int j : tmp) {
				if (!succs[i].contains(j)) {
					return ESat.FALSE;
				}
			}
		}
		if (isCompletelyInstantiated()) {
			return ESat.TRUE;
		}
		return ESat.UNDEFINED;
	}
}