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Open-source constraint solver.
/*
* This file is part of choco-solver, http://choco-solver.org/
*
* Copyright (c) 2023, 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.variables.view.set;
import org.chocosolver.solver.ICause;
import org.chocosolver.solver.exception.ContradictionException;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.solver.variables.Variable;
import org.chocosolver.solver.variables.delta.IIntDeltaMonitor;
import org.chocosolver.solver.variables.delta.ISetDelta;
import org.chocosolver.solver.variables.delta.ISetDeltaMonitor;
import org.chocosolver.solver.variables.delta.SetDelta;
import org.chocosolver.solver.variables.delta.monitor.SetDeltaMonitor;
import org.chocosolver.solver.variables.events.IEventType;
import org.chocosolver.solver.variables.events.SetEventType;
import org.chocosolver.solver.variables.view.SetView;
import org.chocosolver.util.objects.setDataStructures.ISet;
import org.chocosolver.util.objects.setDataStructures.SetFactory;
import org.chocosolver.util.objects.setDataStructures.SetType;
import org.chocosolver.util.procedure.IntProcedure;
import java.util.Arrays;
/**
* Set view over an array of integer variables defined such that:
* with v an array of integers and offset an integer (constants) intVariables[x - offset] = v[x - offset] <=> x in set.
*
* @author Dimitri Justeau-Allaire
* @since 03/2021
*/
public class SetIntsView extends SetView {
/**
* Integer value array such that intVariables[x - offset] = v[x - offset] <=> x in set
*/
private final int[] v;
/**
* Integer value such that intVariables[x - offset] = v[x - offset] <=> x in set
*/
private final int offset;
private final IIntDeltaMonitor[] idm;
private final IntProcedure[] valRemoved;
/**
* Internal bounds only updated by the view.
*/
private final ISet lb;
private final ISet ub;
protected boolean reactOnModification;
private ISetDelta delta;
/**
* Instantiate a set view over an array of integer variables such that:
* intVariables[x - offset] = v[x - offset] <=> x in set
*
* @param name name of the variable
* @param v integer array that "toggle" integer variables index inclusion in the set view.
* Must have the same size as the observed variable array.
* @param offset offset such that if intVariables[x - offset] = v[x - offset] <=> x in set view.
* @param variables observed variables
*/
@SafeVarargs
protected SetIntsView(String name, int[] v, int offset, I... variables) {
super(name, variables);
assert v.length == variables.length;
this.v = v;
this.offset = offset;
this.idm = new IIntDeltaMonitor[getNbObservedVariables()];
this.valRemoved = new IntProcedure[getNbObservedVariables()];
this.lb = SetFactory.makeStoredSet(SetType.BITSET, 0, variables[0].getModel());
this.ub = SetFactory.makeStoredSet(SetType.BITSET, 0, variables[0].getModel());
for (int i = 0; i < getNbObservedVariables(); i++) {
this.idm[i] = getVariables()[i].monitorDelta(this);
this.idm[i].startMonitoring();
int finalI = i;
this.valRemoved[i] = val -> {
if (val == this.v[finalI]) {
this.ub.remove(finalI + offset);
if (reactOnModification) {
delta.add(finalI + offset, SetDelta.UB, this);
}
notifyPropagators(SetEventType.REMOVE_FROM_ENVELOPE, this);
}
};
}
// init
for (int i = 0; i < variables.length; i++) {
if (variables[i].isInstantiatedTo(v[i])) {
lb.add(i + offset);
}
if (variables[i].contains(v[i])) {
ub.add(i + offset);
}
}
}
/**
* Instantiate an set view over an array of integer variables such that:
* intVariables[x - offset] = v[x - offset] <=> x in set
*
* @param v integer array that "toggle" integer variables index inclusion in the set view
* @param offset offset between integer variables indices and set elements.
* @param variables observed variables
*/
@SafeVarargs
public SetIntsView(int[] v, int offset, I... variables) {
this("INTS_SET_VIEW["
+ String.join(",", Arrays.stream(variables)
.map(Variable::getName)
.toArray(String[]::new))
+ "]",
v, offset, variables);
}
@Override
protected boolean doRemoveSetElement(int element) throws ContradictionException {
if (getVariables()[element - this.offset].removeValue(this.v[element - this.offset], this)) {
ub.remove(element);
if (reactOnModification) {
delta.add(element, SetDelta.UB, this);
}
return true;
}
return false;
}
@Override
protected boolean doForceSetElement(int element) throws ContradictionException {
if (getVariables()[element - this.offset].instantiateTo(this.v[element - this.offset], this)) {
lb.add(element);
if (reactOnModification) {
delta.add(element, SetDelta.LB, this);
}
return true;
}
return false;
}
@Override
public void notify(IEventType event, int variableIdx) throws ContradictionException {
if (this.getVariables()[variableIdx].isInstantiatedTo(this.v[variableIdx])) {
lb.add(variableIdx + offset);
if (reactOnModification) {
delta.add(variableIdx + offset, SetDelta.LB, this);
}
notifyPropagators(SetEventType.ADD_TO_KER, this);
} else {
this.idm[variableIdx].forEachRemVal(this.valRemoved[variableIdx]);
}
}
@Override
public ISet getLB() {
return lb;
}
@Override
public ISet getUB() {
return ub;
}
@Override
public boolean instantiateTo(int[] value, ICause cause) throws ContradictionException {
boolean changed = !isInstantiated();
ISet s = SetFactory.makeConstantSet(Arrays.stream(value).map(i -> i - offset).toArray());
for (int i = 0; i < getNbObservedVariables(); i++) {
I var = getVariables()[i];
if (s.contains(i)) {
lb.add(i + offset);
var.instantiateTo(this.v[i], this);
} else {
ub.remove(i + offset);
var.removeValue(this.v[i], this);
}
}
return changed;
}
@Override
public boolean isInstantiated() {
for (int i = 0; i < getNbObservedVariables(); i++) {
if (!getVariables()[i].isInstantiated() && getVariables()[i].contains(this.v[i])) {
return false;
}
}
return true;
}
@Override
public ISetDelta getDelta() {
return delta;
}
@Override
public void createDelta() {
if (!reactOnModification) {
reactOnModification = true;
delta = new SetDelta(model.getEnvironment());
}
}
@Override
public ISetDeltaMonitor monitorDelta(ICause propagator) {
createDelta();
return new SetDeltaMonitor(getDelta(), propagator);
}
}