org.chocosolver.solver.variables.view.integer.IntMinusView Maven / Gradle / Ivy
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/*
* 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.integer;
import org.chocosolver.solver.ICause;
import org.chocosolver.solver.exception.ContradictionException;
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.IEventType;
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 static org.chocosolver.solver.variables.events.IntEventType.BOUND;
import static org.chocosolver.solver.variables.events.IntEventType.DECUPP;
import static org.chocosolver.solver.variables.events.IntEventType.INCLOW;
import static org.chocosolver.solver.variables.events.IntEventType.INSTANTIATE;
/**
* View for -V, where V is a IntVar or view
*
*
* 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 23/08/11
*/
public class IntMinusView extends IntView {
/**
* Create a -var view
* @param var a integer variable
*/
public IntMinusView(final I var) {
super("-(" + var.getName() + ")", var);
}
@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;
}
};
}
@Override
public boolean updateBounds(int lb, int ub, ICause cause) throws ContradictionException {
assert cause != null;
int olb = this.getLB();
int oub = this.getUB();
boolean hasChanged = false;
if (olb < lb || oub > ub) {
IntEventType e = null;
if (olb < lb) {
model.getSolver().getEventObserver().updateLowerBound(this, lb, getLB(), cause);
e = INCLOW;
if (var.updateUpperBound(-lb, this)) {
hasChanged = true;
} else {
model.getSolver().getEventObserver().undo();
}
}
if (oub > ub) {
e = e == null ? DECUPP : BOUND;
model.getSolver().getEventObserver().updateUpperBound(this, ub, getUB(), cause);
if (var.updateLowerBound(-ub, this)) {
hasChanged = true;
} else {
model.getSolver().getEventObserver().undo();
}
}
if (isInstantiated()) {
e = INSTANTIATE;
}
if (hasChanged) {
this.notifyPropagators(e, cause);
}
}
return hasChanged;
}
@Override
protected boolean doInstantiateVar(int value) throws ContradictionException {
return var.instantiateTo(-value, this);
}
@Override
protected boolean doUpdateLowerBoundOfVar(int value) throws ContradictionException {
return var.updateUpperBound(-value, this);
}
@Override
protected boolean doUpdateUpperBoundOfVar(int value) throws ContradictionException {
return var.updateLowerBound(-value, this);
}
@Override
protected boolean doRemoveValueFromVar(int value) throws ContradictionException {
return var.removeValue(-value, this);
}
@Override
protected boolean doRemoveIntervalFromVar(int from, int to) throws ContradictionException {
return var.removeInterval(-to, -from, this);
}
@Override
public boolean contains(int value) {
return var.contains(-value);
}
@Override
public boolean isInstantiatedTo(int value) {
return var.isInstantiatedTo(-value);
}
@Override
public int getValue() throws IllegalStateException{
if(!isInstantiated()) {
throw new IllegalStateException("getValue() can be only called on instantiated variable. " +
name + " is not instantiated");
}
return -var.getValue();
}
@Override
public int getLB() {
return -var.getUB();
}
@Override
public int getUB() {
return -var.getLB();
}
@Override
public int nextValue(int v) {
int value = var.previousValue(-v);
if (value == Integer.MIN_VALUE) return Integer.MAX_VALUE;
return -value;
}
@Override
public int nextValueOut(int v) {
return -var.previousValueOut(-v);
}
@Override
public int previousValue(int v) {
int value = var.nextValue(-v);
if (value == Integer.MAX_VALUE) return Integer.MIN_VALUE;
return -value;
}
@Override
public int previousValueOut(int v) {
return -var.nextValueOut(-v);
}
@Override
protected EvtScheduler createScheduler() {
return new IntEvtScheduler();
}
@Override
public String toString() {
return "-(" + this.var.toString() + ") = [" + 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(false);
}
@Override
public void topDownInit() {
super.topDownInit();
vit = var.getValueIterator(true);
}
@Override
public boolean hasNext() {
return vit.hasPrevious();
}
@Override
public boolean hasPrevious() {
return vit.hasNext();
}
@Override
public int next() {
return -vit.previous();
}
@Override
public int previous() {
return -vit.next();
}
@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(false);
}
@Override
public void topDownInit() {
super.topDownInit();
vir = var.getRangeIterator(true);
}
@Override
public boolean hasNext() {
return vir.hasPrevious();
}
@Override
public boolean hasPrevious() {
return vir.hasNext();
}
@Override
public void next() {
vir.previous();
}
@Override
public void previous() {
vir.next();
}
@Override
public int min() {
return -vir.max();
}
@Override
public int max() {
return -vir.min();
}
@Override
public void dispose() {
super.dispose();
vir.dispose();
}
};
}
if (bottomUp) {
_riterator.bottomUpInit();
} else {
_riterator.topDownInit();
}
return _riterator;
}
@Override
public IEventType transformEvent(IEventType evt) {
if (evt == INCLOW) {
return DECUPP;
} else if (evt == DECUPP) {
return INCLOW;
}
return evt;
}
@Override
public void justifyEvent(IntEventType mask, int one, int two, int three) {
switch (mask) {
case DECUPP:
model.getSolver().getEventObserver().updateLowerBound(this, -one, -two, this);
break;
case INCLOW:
model.getSolver().getEventObserver().updateUpperBound(this, -one, -two, this);
break;
case REMOVE:
model.getSolver().getEventObserver().removeValue(this, -one, this);
break;
case INSTANTIATE:
model.getSolver().getEventObserver().instantiateTo(this, -one, this, -three, -two);
break;
}
}
}