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Open-source constraint solver.
/*
* This file is part of choco-solver, http://choco-solver.org/
*
* Copyright (c) 2022, IMT Atlantique. All rights reserved.
*
* Licensed under the BSD 4-clause license.
*
* See LICENSE file in the project root for full license information.
*/
package org.chocosolver.solver.constraints.set;
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.solver.variables.SetVar;
import org.chocosolver.solver.variables.Variable;
import org.chocosolver.solver.variables.delta.IIntDeltaMonitor;
import org.chocosolver.solver.variables.delta.ISetDeltaMonitor;
import org.chocosolver.solver.variables.events.SetEventType;
import org.chocosolver.util.ESat;
import org.chocosolver.util.objects.setDataStructures.ISetIterator;
import org.chocosolver.util.procedure.IntProcedure;
import org.chocosolver.util.tools.ArrayUtils;
/**
* Channeling between set variables and integer variables
* x in sets[y-offSet1] <=> ints[x-offSet2] = y
*
* @author Jean-Guillaume Fages
*/
public class PropIntChannel extends Propagator {
//***********************************************************************************
// VARIABLES
//***********************************************************************************
private final int nInts;
private final int nSets;
private int idx;
private final SetVar[] sets;
private final IntVar[] ints;
private final int offSet1;
private final int offSet2;
private final ISetDeltaMonitor[] sdm;
private final IIntDeltaMonitor[] idm;
private final IntProcedure elementForced;
private final IntProcedure elementRemoved;
private final IntProcedure valRem;
//***********************************************************************************
// CONSTRUCTORS
//***********************************************************************************
/**
* Channeling between set variables and integer variables
* x in sets[y-offSet1] <=> ints[x-offSet2] = y
*/
public PropIntChannel(SetVar[] setsV, IntVar[] intsV, final int offSet1, final int offSet2) {
super(ArrayUtils.append(setsV, intsV), PropagatorPriority.LINEAR, true);
this.nSets = setsV.length;
this.nInts = intsV.length;
this.sets = new SetVar[nSets];
this.ints = new IntVar[nInts];
this.idm = new IIntDeltaMonitor[nInts];
this.sdm = new ISetDeltaMonitor[nSets];
this.offSet1 = offSet1;
this.offSet2 = offSet2;
for (int i = 0; i < nInts; i++) {
this.ints[i] = (IntVar) vars[i + nSets];
this.idm[i] = this.ints[i].monitorDelta(this);
}
for (int i = 0; i < nSets; i++) {
this.sets[i] = (SetVar) vars[i];
this.sdm[i] = this.sets[i].monitorDelta(this);
}
// procedures
elementForced = element -> ints[element - offSet2].instantiateTo(idx, this);
elementRemoved = element -> ints[element - offSet2].removeValue(idx, this);
valRem = element -> sets[element - offSet1].remove(idx, this);
}
//***********************************************************************************
// METHODS
//***********************************************************************************
@Override
public void propagate(int evtmask) throws ContradictionException {
for (int i = 0; i < nInts; i++) {
ints[i].updateBounds(offSet1, nSets - 1 + offSet1, this);
}
for (int i = 0; i < nInts; i++) {
int ub = ints[i].getUB();
for (int j = ints[i].getLB(); j <= ub; j = ints[i].nextValue(j)) {
if (!sets[j - offSet1].getUB().contains(i + offSet2)) {
ints[i].removeValue(j, this);
}
}
if (ints[i].isInstantiated()) {
sets[ints[i].getValue() - offSet1].force(i + offSet2, this);
}
}
for (int i = 0; i < nSets; i++) {
ISetIterator iter = sets[i].getUB().iterator();
while (iter.hasNext()) {
int j = iter.nextInt();
if (j < offSet2 || j > nInts - 1 + offSet2 || !ints[j - offSet2].contains(i + offSet1)) {
sets[i].remove(j, this);
}
}
iter = sets[i].getLB().iterator();
while (iter.hasNext()) {
ints[iter.nextInt() - offSet2].instantiateTo(i + offSet1, this);
}
}
for (int i = 0; i < nSets; i++) {
sdm[i].startMonitoring();
}
for (int i = 0; i < nInts; i++) {
idm[i].startMonitoring();
}
}
@Override
public void propagate(int idxVarInProp, int mask) throws ContradictionException {
idx = idxVarInProp;
if (idx < nSets) {
idx += offSet1;
sdm[idxVarInProp].forEach(elementForced, SetEventType.ADD_TO_KER);
sdm[idxVarInProp].forEach(elementRemoved, SetEventType.REMOVE_FROM_ENVELOPE);
} else {
idx -= nSets;
if (ints[idx].isInstantiated()) {
sets[ints[idx].getValue() - offSet1].force(idx + offSet2, this);
}
idx += offSet2;
idm[idxVarInProp - nSets].forEachRemVal(valRem);
}
}
@Override
public ESat isEntailed() {
for (int i = 0; i < nInts; i++) {
if (ints[i].isInstantiated()) {
int val = ints[i].getValue();
if (val < offSet1 || val >= nSets + offSet1 || !sets[val - offSet1].getUB().contains(i + offSet2)) {
return ESat.FALSE;
}
}
}
for (int i = 0; i < nSets; i++) {
ISetIterator iter = sets[i].getLB().iterator();
while (iter.hasNext()) {
int j = iter.nextInt();
if (j < offSet2 || j >= nInts + offSet2 || !ints[j - offSet2].contains(i + offSet1)) {
return ESat.FALSE;
}
}
}
if (isCompletelyInstantiated()) {
return ESat.TRUE;
}
return ESat.UNDEFINED;
}
}