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Open-source constraint solver.
/*
* This file is part of choco-solver, http://choco-solver.org/
*
* Copyright (c) 2020, IMT Atlantique. All rights reserved.
*
* Licensed under the BSD 4-clause license.
*
* See LICENSE file in the project root for full license information.
*/
/**
* Created by IntelliJ IDEA.
* User: Jean-Guillaume Fages
* Date: 14/01/13
* Time: 16:36
*/
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.SetVar;
import org.chocosolver.solver.variables.delta.ISetDeltaMonitor;
import org.chocosolver.solver.variables.events.PropagatorEventType;
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;
public class PropIntersection extends Propagator {
//***********************************************************************************
// VARIABLES
//***********************************************************************************
private int k;
private ISetDeltaMonitor[] sdm;
private IntProcedure intersectionForced, intersectionRemoved, setForced, setRemoved;
//***********************************************************************************
// CONSTRUCTORS
//***********************************************************************************
public PropIntersection(SetVar[] sets, SetVar intersection) {
super(ArrayUtils.append(sets, new SetVar[]{intersection}), PropagatorPriority.LINEAR, true);
k = sets.length;
sdm = new ISetDeltaMonitor[k + 1];
for (int i = 0; i <= k; i++) {
sdm[i] = this.vars[i].monitorDelta(this);
}
// PROCEDURES
intersectionForced = element -> {
for (int i = 0; i < k; i++) {
vars[i].force(element, this);
}
};
intersectionRemoved = element -> {
int mate = -1;
for (int i = 0; i < k; i++)
if (vars[i].getUB().contains(element)) {
if (!vars[i].getLB().contains(element)) {
if (mate == -1) {
mate = i;
} else {
mate = -2;
break;
}
}
} else {
mate = -2;
break;
}
if (mate == -1) {
fails(); // TODO: could be more precise, for explanation purpose
} else if (mate != -2) {
vars[mate].remove(element, this);
}
};
setForced = element -> {
boolean allKer = true;
for (int i = 0; i < k; i++) {
if (!vars[i].getUB().contains(element)) {
vars[k].remove(element, this);
allKer = false;
break;
} else if (!vars[i].getLB().contains(element)) {
allKer = false;
}
}
if (allKer) {
vars[k].force(element, this);
}
};
setRemoved = element -> vars[k].remove(element, this);
}
//***********************************************************************************
// METHODS
//***********************************************************************************
@Override
public void propagate(int evtmask) throws ContradictionException {
SetVar intersection = vars[k];
if (PropagatorEventType.isFullPropagation(evtmask)) {
ISetIterator iter = vars[0].getLB().iterator();
while (iter.hasNext()){
int j = iter.nextInt();
boolean all = true;
for (int i = 1; i < k; i++) {
if (!vars[i].getLB().contains(j)) {
all = false;
break;
}
}
if (all) {
intersection.force(j, this);
}
}
iter = intersection.getUB().iterator();
while (iter.hasNext()){
int j = iter.nextInt();
if (intersection.getLB().contains(j)) {
for (int i = 0; i < k; i++) {
vars[i].force(j, this);
}
} else {
for (int i = 0; i < k; i++)
if (!vars[i].getUB().contains(j)) {
intersection.remove(j, this);
break;
}
}
}
// ------------------
for (int i = 0; i <= k; i++)
sdm[i].unfreeze();
}
}
@Override
public void propagate(int idxVarInProp, int mask) throws ContradictionException {
sdm[idxVarInProp].freeze();
if (idxVarInProp < k) {
sdm[idxVarInProp].forEach(setForced, SetEventType.ADD_TO_KER);
sdm[idxVarInProp].forEach(setRemoved, SetEventType.REMOVE_FROM_ENVELOPE);
} else {
sdm[idxVarInProp].forEach(intersectionForced, SetEventType.ADD_TO_KER);
sdm[idxVarInProp].forEach(intersectionRemoved, SetEventType.REMOVE_FROM_ENVELOPE);
}
sdm[idxVarInProp].unfreeze();
}
@Override
public ESat isEntailed() {
ISetIterator iter = vars[k].getLB().iterator();
while (iter.hasNext()) {
int j = iter.nextInt();
for (int i = 0; i < k; i++)
if (!vars[i].getUB().contains(j)) {
return ESat.FALSE;
}
}
iter = vars[0].getLB().iterator();
while (iter.hasNext()){
int j = iter.nextInt();
if (!vars[k].getUB().contains(j)) {
boolean all = true;
for (int i = 1; i < k; i++) {
if (!vars[i].getLB().contains(j)) {
all = false;
break;
}
}
if (all) {
return ESat.FALSE;
}
}
}
if (isCompletelyInstantiated()) return ESat.TRUE;
return ESat.UNDEFINED;
}
}