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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.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.IntVar;
import org.chocosolver.solver.variables.Variable;
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.AbstractVariable;
import org.chocosolver.solver.variables.impl.scheduler.BoolEvtScheduler;
import org.chocosolver.solver.variables.impl.siglit.SignedLiteral;
import org.chocosolver.solver.variables.view.IntView;
import org.chocosolver.solver.variables.view.ViewDeltaMonitor;
import org.chocosolver.util.ESat;
import org.chocosolver.util.iterators.EvtScheduler;
import org.chocosolver.util.objects.setDataStructures.iterable.IntIterableRangeSet;
import org.chocosolver.util.objects.setDataStructures.iterable.IntIterableSet;
/**
* A view for boolean variable, that enforce not(b).
*
* @author Charles Prud'homme
* @since 31/07/12
*/
public final class BoolNotView extends IntView implements BoolVar {
/**
* Create a not view based on var
* @param var a boolean variable
*/
public BoolNotView(B var) {
super("not(" + var.getName() + ")", var);
}
@Override
public ESat getBooleanValue() {
return ESat.not(var.getBooleanValue());
}
@Override
public boolean removeValue(int value, ICause cause) throws ContradictionException {
return contains(value) && instantiateTo(1 - value, cause);
}
@Override
public boolean removeValues(IntIterableSet values, ICause cause) throws ContradictionException {
boolean hasChanged = false;
if (values.contains(0)) {
hasChanged = instantiateTo(1, cause);
}
if (values.contains(1)) {
hasChanged = instantiateTo(0, cause);
}
return hasChanged;
}
@Override
public boolean removeAllValuesBut(IntIterableSet values, ICause cause) throws ContradictionException {
boolean hasChanged = false;
if (!values.contains(0)) {
hasChanged = instantiateTo(1, cause);
}
if (!values.contains(1)) {
hasChanged = instantiateTo(0, cause);
}
return hasChanged;
}
@Override
public boolean removeInterval(int from, int to, ICause cause) throws ContradictionException {
boolean hasChanged = false;
if (from <= to && from <= 1 && to >= 0) {
if (from == 1) {
hasChanged = instantiateTo(0, cause);
} else if (to == 0) {
hasChanged = instantiateTo(1, cause);
} else {
model.getSolver().getEventObserver().instantiateTo(this, 2, cause, 0, 1);
this.contradiction(cause, AbstractVariable.MSG_EMPTY);
}
}
return hasChanged;
}
@Override
public boolean instantiateTo(int value, ICause cause) throws ContradictionException {
if (!this.contains(value)) {
model.getSolver().getEventObserver().instantiateTo(this, value, cause, getLB(), getUB());
this.contradiction(cause, MSG_INST);
} else if (!isInstantiated()) {
model.getSolver().getEventObserver().instantiateTo(this, value, cause, getLB(), getUB());
boolean done = var.instantiateTo(1 - value, this);
notifyPropagators(IntEventType.INSTANTIATE, cause);
return done;
}
return false;
}
@Override
public boolean updateLowerBound(int value, ICause cause) throws ContradictionException {
return value > 0 && instantiateTo(value, cause);
}
@Override
public boolean updateUpperBound(int value, ICause cause) throws ContradictionException {
return value < 1 && instantiateTo(value, cause);
}
@Override
public boolean updateBounds(int lb, int ub, ICause cause) throws ContradictionException {
boolean hasChanged = false;
if (lb > 1) {
var.instantiateTo(-1, cause);
} else if (ub < 0) {
var.instantiateTo(2, cause);
} else {
if (lb == 1) {
hasChanged = instantiateTo(1, cause);
}
if (ub == 0) {
hasChanged = instantiateTo(0, cause);
}
}
return hasChanged;
}
@Override
public boolean contains(int value) {
return var.contains(1 - value);
}
@Override
public boolean isInstantiatedTo(int value) {
return var.isInstantiatedTo(1 - value);
}
@Override
public int getValue() {
int v = var.getValue();
return 1 - v;
}
@Override
public int getLB() {
if (var.isInstantiated()) {
return getValue();
} else return 0;
}
@Override
public int getUB() {
if (var.isInstantiated()) {
return getValue();
} else return 1;
}
@Override
public int nextValue(int v) {
if (v < 0 && contains(0)) {
return 0;
}
return v <= 0 && contains(1) ? 1 : Integer.MAX_VALUE;
}
@Override
public int nextValueOut(int v) {
int lb = 0, ub = 1;
if (var.isInstantiated()) {
lb = ub = getValue();
}
if (lb - 1 <= v && v <= ub) {
return ub + 1;
} else {
return v + 1;
}
}
@Override
public int previousValue(int v) {
if (v > 1 && contains(1)) {
return 1;
}
return v >= 1 && contains(0) ? 0 : Integer.MIN_VALUE;
}
@Override
public int previousValueOut(int v) {
int lb = 0, ub = 1;
if (var.isInstantiated()) {
lb = ub = getValue();
}
if (lb <= v && v <= ub + 1) {
return lb - 1;
} else {
return v - 1;
}
}
@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 1 - value;
}
};
}
@Override
protected EvtScheduler createScheduler() {
return new BoolEvtScheduler();
}
public String toString() {
return "not(" + var + ")";
}
@Override
public BoolVar not() {
return var;
}
@Override
public void _setNot(BoolVar not) {
assert not == var;
}
@Override
public boolean hasNot() {
return true;
}
@Override
public boolean isLit() {
return true;
}
@Override
public boolean isNot() {
return !var.isNot();
}
@Override
public void setNot(boolean isNot) {
assert isNot;
}
@Override
public int getTypeAndKind() {
return Variable.VIEW | Variable.BOOL;
}
@Override
public void justifyEvent(IntEventType mask, int one, int two, int three) {
assert mask == IntEventType.INSTANTIATE;
model.getSolver().getEventObserver().instantiateTo(this, 1 - one, this, 0, 1);
}
@Override
public void explain(int p, ExplanationForSignedClause explanation) {
IntVar pivot = explanation.readVar(p);
if(this == pivot){
this.intersectLit(getValue(), explanation);
var.unionLit(getValue(), explanation);
}else{
this.unionLit(1 - getValue(), explanation);
var.intersectLit(1 - getValue(), explanation);
}
}
@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;
}
}