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package solver.constraints.nary.alldifferent;
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 util.ESat;
/**
* Propagator for AllDifferent AC constraint for integer variables
* <p/>
* Uses Regin algorithm
* Runs in O(m.n) worst case time for the initial propagation
* but has a good average behavior in practice
* <p/>
* Runs incrementally for maintaining a matching
* <p/>
*
* @author Jean-Guillaume Fages
*/
public class PropAllDiffAC extends Propagator<IntVar> {
//***********************************************************************************
// VARIABLES
//***********************************************************************************
AlgoAllDiffAC filter;
//***********************************************************************************
// CONSTRUCTORS
//***********************************************************************************
/**
* AllDifferent constraint for integer variables
* enables to control the cardinality of the matching
*
* @param variables
*/
public PropAllDiffAC(IntVar[] variables) {
super(variables, PropagatorPriority.QUADRATIC, false);
this.filter = new AlgoAllDiffAC(variables, aCause);
}
//***********************************************************************************
// PROPAGATION
//***********************************************************************************
@Override
public void propagate(int evtmask) throws ContradictionException {
filter.propagate();
}
@Override
public ESat isEntailed() {
return ESat.TRUE; // redundant propagator (used with PropAllDiffInst)
}
@Override
public void duplicate(Solver solver, THashMap<Object, Object> identitymap) {
if (!identitymap.containsKey(this)) {
IntVar[] aVars = new IntVar[this.vars.length];
for (int i = 0; i < this.vars.length; i++) {
this.vars[i].duplicate(solver, identitymap);
aVars[i] = (IntVar) identitymap.get(this.vars[i]);
}
identitymap.put(this, new PropAllDiffAC(aVars));
}
}
}