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package solver.constraints.nary.alldifferent.conditions;
import gnu.trove.map.hash.THashMap;
import solver.Solver;
import solver.constraints.Propagator;
import solver.constraints.PropagatorPriority;
import solver.constraints.nary.alldifferent.algo.AlgoAllDiffAC;
import solver.exception.ContradictionException;
import solver.variables.IntVar;
import solver.variables.events.PropagatorEventType;
import util.ESat;
/**
* Propagator for AllDifferent AC constraint for integer variables
* subject to conditions (e.g. allDifferent_except_0)
* AllDiff only applies on the subset of variables satisfying the given condition
*
* @author Jean-Guillaume Fages
*/
public class PropCondAllDiff_AC extends Propagator<IntVar> {
private Condition condition;
private AlgoAllDiffAC filter;
//***********************************************************************************
// CONSTRUCTORS
//***********************************************************************************
/**
* AllDifferent constraint for integer variables
* Holds only on the subset of variables satisfying the given condition
*
* @param variables
* @param condition defines the subset of variables which is considered by the
* alldifferent constraint
*/
public PropCondAllDiff_AC(IntVar[] variables, Condition condition) {
super(variables, PropagatorPriority.QUADRATIC, false);
this.condition = condition;
}
//***********************************************************************************
// PROPAGATION
//***********************************************************************************
@Override
public void propagate(int evtmask) throws ContradictionException {
int nb = 0;
for (IntVar v : vars) {
if (condition.holdOnVar(v)) {
nb++;
}
}
IntVar[] vs = new IntVar[nb];
for (IntVar v : vars) {
if (condition.holdOnVar(v)) {
nb--;
vs[nb] = v;
}
}
filter = new AlgoAllDiffAC(vs, aCause);
filter.propagate();
}
@Override
public void propagate(int varIdx, int mask) throws ContradictionException {
forcePropagate(PropagatorEventType.CUSTOM_PROPAGATION);
}
//***********************************************************************************
// INFO
//***********************************************************************************
@Override
public ESat isEntailed() {
int nbInst = 0;
for (int i = 0; i < vars.length; i++) {
if (vars[i].isInstantiated()) {
nbInst++;
if (condition.holdOnVar(vars[i])) {
for (int j = i + 1; j < vars.length; j++) {
if (condition.holdOnVar(vars[j]))
if (vars[j].isInstantiated() && vars[i].getValue() == vars[j].getValue()) {
return ESat.FALSE;
}
}
}
}
}
if (nbInst == vars.length) {
return ESat.TRUE;
}
return ESat.UNDEFINED;
}
@Override
public void duplicate(Solver solver, THashMap<Object, Object> identitymap) {
if (!identitymap.containsKey(this)) {
int size = this.vars.length;
IntVar[] aVars = new IntVar[size];
for (int i = 0; i < size; i++) {
this.vars[i].duplicate(solver, identitymap);
aVars[i] = (IntVar) identitymap.get(this.vars[i]);
}
identitymap.put(this, new PropCondAllDiff_AC(aVars, this.condition));
}
}
}