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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.bool;
import org.chocosolver.memory.IStateBool;
import org.chocosolver.solver.ICause;
import org.chocosolver.solver.exception.ContradictionException;
import org.chocosolver.solver.learn.ExplanationForSignedClause;
import org.chocosolver.solver.variables.BoolVar;
import org.chocosolver.solver.variables.SetVar;
import org.chocosolver.solver.variables.Variable;
import org.chocosolver.solver.variables.delta.IDelta;
import org.chocosolver.solver.variables.delta.IEnumDelta;
import org.chocosolver.solver.variables.delta.IIntDeltaMonitor;
import org.chocosolver.solver.variables.delta.NoDelta;
import org.chocosolver.solver.variables.delta.monitor.OneValueDeltaMonitor;
import org.chocosolver.solver.variables.events.IEventType;
import org.chocosolver.solver.variables.events.IntEventType;
import org.chocosolver.solver.variables.impl.AbstractVariable;
import org.chocosolver.solver.variables.impl.scheduler.BoolEvtScheduler;
import org.chocosolver.solver.variables.impl.siglit.SignedLiteral;
import org.chocosolver.solver.variables.view.AbstractView;
import org.chocosolver.util.ESat;
import org.chocosolver.util.iterators.*;
import org.chocosolver.util.objects.setDataStructures.iterable.IntIterableRangeSet;
import org.chocosolver.util.objects.setDataStructures.iterable.IntIterableSet;
import java.util.Iterator;
/**
* Boolean view b over a set variable S:
*
* With v an integer, b = true iff S contains v.
*
* @author Dimitri Justeau-Allaire
* @since 08/2021
*/
public class BoolSetView extends AbstractView implements BoolVar {
/**
* The observed set variables
*/
protected S setVar;
/**
* The value to observe in the set variable
*/
protected int v;
/**
* To iterate over removed values
*/
protected IEnumDelta delta = NoDelta.singleton;
/**
* Set to true if this variable reacts is associated with at least one propagator which
* reacts on value removal
*/
protected boolean reactOnRemoval = false;
/**
* indicate if the view is fixed
*/
protected IStateBool fixed;
/**
* Associate boolean variable expressing not(this)
*/
private BoolVar not;
/**
* For boolean expression purpose
*/
private boolean isNot = false;
/**
* Value iterator
*/
protected DisposableValueIterator _viterator;
/**
* Range iterator
*/
protected DisposableRangeIterator _riterator;
/**
* Value iterator allowing for(int i:this) loops
*/
private final IntVarValueIterator _javaIterator = new IntVarValueIterator(this);
/**
* Signed Literal
*/
protected SignedLiteral literal;
public BoolSetView(int v, S setVar) {
super("boolSetView[" + v + " in " + setVar.getName() + "]", setVar);
this.setVar = setVar;
this.v = v;
boolean initialValue = setVar.getLB().contains(v) || !setVar.getUB().contains(v);
this.fixed = getModel().getEnvironment().makeBool(initialValue);
}
// BoolVar methods
@Override
public ESat getBooleanValue() {
if (setVar.getLB().contains(v)) {
return ESat.TRUE;
}
if (!setVar.getUB().contains(v)) {
return ESat.FALSE;
}
return ESat.UNDEFINED;
}
public void notify(IEventType event, int variableIdx) throws ContradictionException {
if (!fixed.get() && isInstantiated()) {
fixed.set(true);
notifyPropagators(event, this);
}
}
@Override
public boolean instantiateTo(int value, ICause cause) throws ContradictionException {
assert cause != null;
boolean done = false;
if (!this.contains(value)) {
model.getSolver().getEventObserver().instantiateTo(this, v, cause, getLB(), getUB());
this.contradiction(cause, MSG_EMPTY);
} else if (!isInstantiated()) {
model.getSolver().getEventObserver().instantiateTo(this, value, cause, getLB(), getUB());
this.fixed.set(true);
if (reactOnRemoval) {
delta.add(1 - value, cause);
}
if (value == 1) {
done = setVar.force(v, this);
} else {
done = setVar.remove(v, this);
}
notifyPropagators(IntEventType.INSTANTIATE, cause);
}
return done;
}
@Override
public boolean contains(int value) {
if (value == 0) {
return !setVar.getLB().contains(v);
} else if (value == 1) {
return setVar.getUB().contains(v);
}
return false;
}
@Override
public boolean isInstantiated() {
if (setVar.getLB().contains(v)) {
return true;
}
return !setVar.getUB().contains(v);
}
@Override
public boolean isInstantiatedTo(int value) {
if (value == 0) {
return !setVar.getUB().contains(v);
} else if (value == 1) {
return setVar.getLB().contains(v);
}
return false;
}
@Override
public int getDomainSize() {
return isInstantiated() ? 1 : 2;
}
@Override
public int getRange() {
return getUB() - getLB();
}
@Override
public boolean hasEnumeratedDomain() {
return false;
}
@Override
public int getLB() {
if (setVar.getLB().contains(v)) {
return 1;
}
return 0;
}
@Override
public int getUB() {
if (setVar.getUB().contains(v)) {
return 1;
}
return 0;
}
@Override
public int nextValue(int val) {
if (val < 0 && contains(0)) {
return 0;
}
return val <= 0 && contains(1) ? 1 : Integer.MAX_VALUE;
}
@Override
public final int getTypeAndKind() {
return Variable.VIEW | Variable.BOOL;
}
@Override
public final int getValue() {
return getLB();
}
@Override
protected final BoolEvtScheduler createScheduler() {
return new BoolEvtScheduler();
}
@Override
public IDelta getDelta() {
return delta;
}
@Override
public void createDelta() {
setVar.createDelta();
}
@Override
public final IIntDeltaMonitor monitorDelta(ICause propagator) {
createDelta();
return new OneValueDeltaMonitor(delta, propagator);
}
@Override
public final void _setNot(BoolVar neg) {
this.not = neg;
}
@Override
public final BoolVar not() {
if (!hasNot()) {
not = model.boolNotView(this);
not._setNot(this);
}
return not;
}
@Override
public final boolean hasNot() {
return not != null;
}
@Override
public final boolean isLit() {
return true;
}
@Override
public final boolean isNot() {
return isNot;
}
@Override
public final void setNot(boolean isNot) {
this.isNot = isNot;
}
@Override
public int nextValueOut(int val) {
int lb = getLB();
int ub = getUB();
if (lb - 1 <= val && val <= ub) {
return ub + 1;
} else {
return val + 1;
}
}
@Override
public int previousValue(int val) {
if (val > 1 && contains(1)) {
return 1;
}
return val >= 1 && contains(0) ? 0 : Integer.MIN_VALUE;
}
@Override
public int previousValueOut(int val) {
int lb = getLB();
int ub = getUB();
if (lb <= val && val <= ub + 1) {
return lb - 1;
} else {
return val - 1;
}
}
@Override
public final boolean removeValue(int value, ICause cause) throws ContradictionException {
assert cause != null;
if (value == kFALSE)
return instantiateTo(kTRUE, cause);
else if (value == kTRUE)
return instantiateTo(kFALSE, cause);
return false;
}
@Override
public final boolean removeValues(IntIterableSet values, ICause cause) throws ContradictionException {
boolean hasChanged = false;
if (values.contains(kFALSE)) {
hasChanged = instantiateTo(kTRUE, cause);
}
if (values.contains(kTRUE)) {
hasChanged = instantiateTo(kFALSE, cause);
}
return hasChanged;
}
@Override
public final boolean removeAllValuesBut(IntIterableSet values, ICause cause) throws ContradictionException {
boolean hasChanged = false;
if (!values.contains(kFALSE)) {
hasChanged = instantiateTo(kTRUE, cause);
}
if (!values.contains(kTRUE)) {
hasChanged = instantiateTo(kFALSE, cause);
}
return hasChanged;
}
@Override
public final boolean removeInterval(int from, int to, ICause cause) throws ContradictionException {
boolean hasChanged = false;
if (from <= to && from <= 1 && to >= 0) {
if (from == kTRUE) {
hasChanged = instantiateTo(kFALSE, cause);
} else if (to == kFALSE) {
hasChanged = instantiateTo(kTRUE, cause);
} else {
model.getSolver().getEventObserver().instantiateTo(this, 2, cause, kFALSE, kTRUE);
this.contradiction(cause, AbstractVariable.MSG_EMPTY);
}
}
return hasChanged;
}
@Override
public final boolean updateLowerBound(int value, ICause cause) throws ContradictionException {
assert cause != null;
return value > kFALSE && instantiateTo(value, cause);
}
@Override
public final boolean updateUpperBound(int value, ICause cause) throws ContradictionException {
assert cause != null;
return value < kTRUE && instantiateTo(value, cause);
}
@Override
public final boolean updateBounds(int lb, int ub, ICause cause) throws ContradictionException {
boolean hasChanged = false;
if (lb > kTRUE || ub < kFALSE) {
model.getSolver().getEventObserver().instantiateTo(this, 2, cause, kFALSE, kTRUE);
this.contradiction(cause, MSG_EMPTY);
} else {
if (lb == kTRUE) {
hasChanged = instantiateTo(kTRUE, cause);
}
if (ub == kFALSE) {
hasChanged = instantiateTo(kFALSE, cause);
}
}
return hasChanged;
}
@Override
public final DisposableValueIterator getValueIterator(boolean bottomUp) {
if (_viterator == null || _viterator.isNotReusable()) {
_viterator = new DisposableValueBoundIterator(this);
}
if (bottomUp) {
_viterator.bottomUpInit();
} else {
_viterator.topDownInit();
}
return _viterator;
}
@Override
public final DisposableRangeIterator getRangeIterator(boolean bottomUp) {
if (_riterator == null || _riterator.isNotReusable()) {
_riterator = new DisposableRangeBoundIterator(this);
}
if (bottomUp) {
_riterator.bottomUpInit();
} else {
_riterator.topDownInit();
}
return _riterator;
}
@Override
public Iterator iterator() {
_javaIterator.reset();
return _javaIterator;
}
@Override
public void createLit(IntIterableRangeSet rootDomain) {
if(this.literal != null){
throw new IllegalStateException("createLit(Implications) called twice");
}
this.literal = new SignedLiteral.Boolean();
}
@Override
public SignedLiteral getLit() {
if (this.literal == null) {
throw new NullPointerException("getLit() called on null, a call to createLit(Implications) is required");
}
return this.literal;
}
@Override
public void justifyEvent(IntEventType mask, int one, int two, int three) {
throw new UnsupportedOperationException("Bool view over set variables does not support explanations");
}
@Override
public void explain(int p, ExplanationForSignedClause explanation) {
throw new UnsupportedOperationException("Bool view over set variables does not support explanations");
}
}