org.chocosolver.parser.flatzinc.ast.constraints.IntLeReifBuilder Maven / Gradle / Ivy
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* Copyright (c) 1999-2011, Ecole des Mines de Nantes
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package org.chocosolver.parser.flatzinc.ast.constraints;
import org.chocosolver.parser.flatzinc.FznSettings;
import org.chocosolver.parser.flatzinc.ast.Datas;
import org.chocosolver.parser.flatzinc.ast.expression.EAnnotation;
import org.chocosolver.parser.flatzinc.ast.expression.Expression;
import org.chocosolver.solver.Solver;
import org.chocosolver.solver.constraints.*;
import org.chocosolver.solver.exception.ContradictionException;
import org.chocosolver.solver.explanations.RuleStore;
import org.chocosolver.solver.variables.BoolVar;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.solver.variables.Variable;
import org.chocosolver.solver.variables.events.IEventType;
import org.chocosolver.solver.variables.events.IntEventType;
import org.chocosolver.util.ESat;
import java.util.List;
/**
* (a ≤ b) ⇔ r
*
*
* @author Charles Prud'homme, Jean-Guillaume Fages
* @since 26/01/11
*/
public class IntLeReifBuilder implements IBuilder {
@Override
public void build(Solver solver, String name, List exps, List annotations, Datas datas) {
IntVar a = exps.get(0).intVarValue(solver);
IntVar b = exps.get(1).intVarValue(solver);
final BoolVar r = exps.get(2).boolVarValue(solver);
// this constraint is not poster, hence not returned, because it is reified
if (((FznSettings) solver.getSettings()).enableClause()
&& ((a.getTypeAndKind() & Variable.KIND) == Variable.BOOL) && ((b.getTypeAndKind() & Variable.KIND) == Variable.BOOL)) {
SatFactory.addBoolIsLeVar((BoolVar) a, (BoolVar) b, r);
} else {
if (((FznSettings) solver.getSettings()).adhocReification()) {
if (a.isInstantiated() || b.isInstantiated()) {
final IntVar var;
final int cste;
if (a.isInstantiated()) {
var = b;
cste = a.getValue();
solver.post(new Constraint("reif(a>=cste,r)", new Propagator(new IntVar[]{var, r}, PropagatorPriority.BINARY, false) {
@Override
public void propagate(int evtmask) throws ContradictionException {
if (r.getLB() == 1) {
setPassive();
var.updateLowerBound(cste, this);
} else {
if (r.getUB() == 0) {
if (var.updateUpperBound(cste - 1, this)) {
setPassive();
}
} else {
if (var.getLB() >= cste) {
setPassive();
r.setToTrue(this);
} else if (var.getUB() < cste) {
setPassive();
r.setToFalse(this);
}
}
}
}
@Override
public ESat isEntailed() {
// throw new UnsupportedOperationException("isEntailed not implemented ");
return ESat.TRUE;
}
@Override
public boolean why(RuleStore ruleStore, IntVar var, IEventType evt, int value) {
boolean nrules = ruleStore.addPropagatorActivationRule(this);
if (var == vars[1]) { // r
if (vars[1].isInstantiatedTo(1)) {
nrules |= ruleStore.addLowerBoundRule(vars[0]);
} else {
nrules |= ruleStore.addUpperBoundRule(vars[0]);
}
} else { //
nrules |= ruleStore.addFullDomainRule(vars[1]);
}
return nrules;
}
}));
} else {
var = a;
cste = b.getValue();
solver.post(new Constraint("reif(a<=cste,r)", new Propagator(new IntVar[]{var, r}, PropagatorPriority.BINARY, false) {
@Override
public void propagate(int evtmask) throws ContradictionException {
if (r.getLB() == 1) {
setPassive();
var.updateUpperBound(cste, this);
} else {
if (r.getUB() == 0) {
if (var.updateLowerBound(cste + 1, this)) {
setPassive();
}
} else {
if (var.getUB() <= cste) {
setPassive();
r.setToTrue(this);
} else if (var.getLB() > cste) {
setPassive();
r.setToFalse(this);
}
}
}
}
@Override
public ESat isEntailed() {
// throw new UnsupportedOperationException("isEntailed not implemented ");
return ESat.TRUE;
}
@Override
public boolean why(RuleStore ruleStore, IntVar var, IEventType evt, int value) {
boolean nrules = ruleStore.addPropagatorActivationRule(this);
if (var == vars[1]) {
if (vars[1].isInstantiatedTo(1)) {
nrules |= ruleStore.addUpperBoundRule(vars[0]);
} else {
nrules |= ruleStore.addLowerBoundRule(vars[0]);
}
} else {
nrules |= ruleStore.addFullDomainRule(vars[1]);
}
return nrules;
}
}));
}
} else {
solver.post(new Constraint("reif(a<=b,r)", new Propagator(new IntVar[]{a, b, r}, PropagatorPriority.TERNARY, false) {
@Override
public void propagate(int evtmask) throws ContradictionException {
if (r.getLB() == 1) {
vars[0].updateUpperBound(vars[1].getUB(), this);
vars[1].updateLowerBound(vars[0].getLB(), this);
if (vars[0].getUB() <= vars[1].getLB()) {
this.setPassive();
}
} else {
if (r.getUB() == 0) {
vars[0].updateLowerBound(vars[1].getLB() + 1, this);
vars[1].updateUpperBound(vars[0].getUB() - 1, this);
if (vars[0].getLB() > vars[1].getUB()) {
setPassive();
}
} else {
if (vars[0].getUB() <= vars[1].getLB()) {
setPassive();
r.setToTrue(this);
} else if (vars[0].getLB() > vars[1].getUB()) {
setPassive();
r.setToFalse(this);
}
}
}
}
@Override
public ESat isEntailed() {
throw new UnsupportedOperationException("isEntailed not implemented ");
}
@Override
public boolean why(RuleStore ruleStore, IntVar var, IEventType evt, int value) {
boolean nrules = ruleStore.addPropagatorActivationRule(this);
if (var == vars[2]) {
if (vars[2].isInstantiatedTo(1)) {
nrules |= ruleStore.addUpperBoundRule(vars[0]);
nrules |= ruleStore.addLowerBoundRule(vars[1]);
} else {
nrules |= ruleStore.addLowerBoundRule(vars[0]);
nrules |= ruleStore.addUpperBoundRule(vars[1]);
}
} else {
if (var == vars[0]) {
if (evt == IntEventType.DECUPP) {
nrules |= ruleStore.addUpperBoundRule(vars[1]);
} else {
nrules |= ruleStore.addLowerBoundRule(vars[1]);
}
} else if (var == vars[1]) {
if (evt == IntEventType.DECUPP) {
nrules |= ruleStore.addUpperBoundRule(vars[0]);
} else {
nrules |= ruleStore.addLowerBoundRule(vars[0]);
}
}
nrules |= ruleStore.addFullDomainRule(vars[2]);
}
return nrules;
}
}));
}
} else {
ICF.arithm(a, "<=", b).reifyWith(r);
}
}
}
}
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