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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.variables.view.integer;
import org.chocosolver.solver.ICause;
import org.chocosolver.solver.exception.ContradictionException;
import org.chocosolver.solver.learn.ExplanationForSignedClause;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.solver.variables.delta.IIntDeltaMonitor;
import org.chocosolver.solver.variables.delta.NoDelta;
import org.chocosolver.solver.variables.events.IntEventType;
import org.chocosolver.solver.variables.impl.scheduler.IntEvtScheduler;
import org.chocosolver.solver.variables.view.IntView;
import org.chocosolver.solver.variables.view.ViewDeltaMonitor;
import org.chocosolver.util.iterators.DisposableRangeIterator;
import org.chocosolver.util.iterators.DisposableValueIterator;
import org.chocosolver.util.iterators.EvtScheduler;
import org.chocosolver.util.objects.setDataStructures.iterable.IntIterableRangeSet;
/**
* declare an IntVar based on X and C, such as X + C
*
* Based on "Views and Iterators for Generic Constraint Implementations"
* C. Shulte and G. Tack.
* Eleventh International Conference on Principles and Practice of Constraint Programming
*
* @author Charles Prud'homme
* @since 04/02/11
*/
public final class IntOffsetView extends IntView {
/**
* A constant value
*/
public final int cste;
/**
* A view based on var such that var + cste
* @param var an integer variable
* @param cste an int
*/
public IntOffsetView(final I var, final int cste) {
super("(" + var.getName() + "+" + cste + ")", var);
this.cste = cste;
}
@Override
public IIntDeltaMonitor monitorDelta(ICause propagator) {
var.createDelta();
if (var.getDelta() == NoDelta.singleton) {
return IIntDeltaMonitor.Default.NONE;
}
return new ViewDeltaMonitor(var.monitorDelta(propagator)) {
@Override
protected int transform(int value) {
return value + cste;
}
};
}
@Override
protected boolean doInstantiateVar(int value) throws ContradictionException {
return var.instantiateTo(value - cste, this);
}
@Override
protected boolean doUpdateLowerBoundOfVar(int value) throws ContradictionException {
return var.updateLowerBound(value - cste, this);
}
@Override
protected boolean doUpdateUpperBoundOfVar(int value) throws ContradictionException {
return var.updateUpperBound(value - cste, this);
}
@Override
protected boolean doRemoveValueFromVar(int value) throws ContradictionException {
return var.removeValue(value - cste, this);
}
@Override
protected boolean doRemoveIntervalFromVar(int from, int to) throws ContradictionException {
return var.removeInterval(from - cste, to - cste, this);
}
@Override
public boolean contains(int value) {
return var.contains(value - cste);
}
@Override
public boolean isInstantiatedTo(int value) {
return var.isInstantiatedTo(value - cste);
}
@Override
public int getValue() {
return var.getValue() + cste;
}
@Override
public int getLB() {
return var.getLB() + cste;
}
@Override
public int getUB() {
return var.getUB() + cste;
}
@Override
public int nextValue(int v) {
int value = var.nextValue(v - cste);
if (value == Integer.MAX_VALUE) {
return value;
}
return value + cste;
}
@Override
public int nextValueOut(int v) {
return var.nextValueOut(v - cste) + cste;
}
@Override
public int previousValue(int v) {
int value = var.previousValue(v - cste);
if (value == Integer.MIN_VALUE) {
return Integer.MIN_VALUE;
}
return value + cste;
}
@Override
public int previousValueOut(int v) {
return var.previousValueOut(v - cste) + cste;
}
@Override
protected EvtScheduler createScheduler() {
return new IntEvtScheduler();
}
@Override
public String toString() {
return "(" + var.toString() + (cste >= 0 ? " + " : " - ") + Math.abs(cste) + ") = [" + getLB() + "," + getUB() + "]";
}
@Override
public DisposableValueIterator getValueIterator(boolean bottomUp) {
if (_viterator == null || _viterator.isNotReusable()) {
_viterator = new DisposableValueIterator() {
DisposableValueIterator vit;
@Override
public void bottomUpInit() {
super.bottomUpInit();
vit = var.getValueIterator(true);
}
@Override
public void topDownInit() {
super.topDownInit();
vit = var.getValueIterator(false);
}
@Override
public boolean hasNext() {
return vit.hasNext();
}
@Override
public boolean hasPrevious() {
return vit.hasPrevious();
}
@Override
public int next() {
return vit.next() + cste;
}
@Override
public int previous() {
return vit.previous() + cste;
}
@Override
public void dispose() {
super.dispose();
vit.dispose();
}
};
}
if (bottomUp) {
_viterator.bottomUpInit();
} else {
_viterator.topDownInit();
}
return _viterator;
}
@Override
public DisposableRangeIterator getRangeIterator(boolean bottomUp) {
if (_riterator == null || _riterator.isNotReusable()) {
_riterator = new DisposableRangeIterator() {
DisposableRangeIterator vir;
@Override
public void bottomUpInit() {
super.bottomUpInit();
vir = var.getRangeIterator(true);
}
@Override
public void topDownInit() {
super.topDownInit();
vir = var.getRangeIterator(false);
}
@Override
public boolean hasNext() {
return vir.hasNext();
}
@Override
public boolean hasPrevious() {
return vir.hasPrevious();
}
@Override
public void next() {
vir.next();
}
@Override
public void previous() {
vir.previous();
}
@Override
public int min() {
return vir.min() + cste;
}
@Override
public int max() {
return vir.max() + cste;
}
@Override
public void dispose() {
super.dispose();
vir.dispose();
}
};
}
if (bottomUp) {
_riterator.bottomUpInit();
} else {
_riterator.topDownInit();
}
return _riterator;
}
@Override
public void justifyEvent(IntEventType mask, int one, int two, int three) {
switch (mask) {
case DECUPP:
model.getSolver().getEventObserver().updateUpperBound(this, one + cste, two + cste, this);
break;
case INCLOW:
model.getSolver().getEventObserver().updateLowerBound(this, one + cste, two + cste, this);
break;
case REMOVE:
model.getSolver().getEventObserver().removeValue(this, one + cste, this);
break;
case INSTANTIATE:
model.getSolver().getEventObserver().instantiateTo(this, one + cste, this, two + cste, three + cste);
break;
}
}
@Override
public void explain(int p, ExplanationForSignedClause explanation) {
IntIterableRangeSet set0, set1;
if (explanation.readVar(p) == this) { // case a. (see javadoc)
set1 = explanation.complement(getVariable());
set0 = explanation.domain(getVariable());
set0.plus(cste);
this.intersectLit(set0, explanation);
getVariable().unionLit(set1, explanation);
} else { // case b. (see javadoc)
assert explanation.readVar(p) == getVariable();
set0 = explanation.complement(this);
set1 = explanation.domain(this);
set1.minus(cste);
this.unionLit(set0, explanation);
getVariable().intersectLit(set1, explanation);
}
}
}