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*
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* documentation and/or other materials provided with the distribution.
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* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
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/**
* Created by IntelliJ IDEA.
* User: Jean-Guillaume Fages
* Date: 18/06/12
* Time: 18:32
*/
package solver.constraints.nary.sum;
import gnu.trove.map.hash.THashMap;
import memory.IEnvironment;
import memory.IStateInt;
import solver.Solver;
import solver.constraints.Propagator;
import solver.constraints.PropagatorPriority;
import solver.exception.ContradictionException;
import solver.variables.BoolVar;
import solver.variables.IntVar;
import solver.variables.events.IntEventType;
import util.ESat;
import util.tools.ArrayUtils;
/**
* Constraint that state that the sum of boolean variables vars is equal to the integer variable sum
* Works incrementally in O(1) per instantiation event
*/
public class PropBoolSumIncremental extends Propagator<IntVar> {
//***********************************************************************************
// VARIABLES
//***********************************************************************************
IntVar sum;
int n;
IStateInt min, max;
//***********************************************************************************
// CONSTRUCTORS
//***********************************************************************************
/**
* Constraint that state that the sum of boolean variables vars is equal to the integer variable sum
* Works in O(1) per instantiation event
*
* @param variables
* @param sum
*/
public PropBoolSumIncremental(BoolVar[] variables, IntVar sum) {
super(ArrayUtils.append(variables, new IntVar[]{sum}), PropagatorPriority.UNARY, true);
n = variables.length;
this.sum = vars[n];
IEnvironment environment = solver.getEnvironment();
min = environment.makeInt();
max = environment.makeInt();
}
//***********************************************************************************
// METHODS
//***********************************************************************************
@Override
public void propagate(int evtmask) throws ContradictionException {
int lb = 0;
int ub = 0;
for (int i = 0; i < n; i++) {
lb += vars[i].getLB();
ub += vars[i].getUB();
}
min.set(lb);
max.set(ub);
filter();
}
private void filter() throws ContradictionException {
int lb = min.get();
int ub = max.get();
sum.updateLowerBound(lb, aCause);
sum.updateUpperBound(ub, aCause);
if (lb != ub && sum.isInstantiated()) {
if (sum.getValue() == lb) {
for (int i = 0; i < n; i++) {
if (!vars[i].isInstantiated()) {
vars[i].instantiateTo(0, aCause);
}
}
}
if (sum.getValue() == ub) {
for (int i = 0; i < n; i++) {
if (!vars[i].isInstantiated()) {
vars[i].instantiateTo(1, aCause);
}
}
}
// remarque : ne pas mettre de setPassive() car:
// 1) C'est inutile : tout est instancie
// 2) Il faudrait verifier que tous les evenements ont bien ete depiles
}
}
@Override
public void propagate(int idxVarInProp, int mask) throws ContradictionException {
if (idxVarInProp < n) {
if (vars[idxVarInProp].getValue() == 1) {
min.add(1);
} else {
max.add(-1);
}
}
filter();
}
@Override
public int getPropagationConditions(int vIdx) {
if (vIdx == n)
return IntEventType.boundAndInst();
return IntEventType.instantiation();
}
@Override
public ESat isEntailed() {
int lb = 0;
int ub = 0;
for (int i = 0; i < n; i++) {
lb += vars[i].getLB();
ub += vars[i].getUB();
}
if (lb > sum.getUB() || ub < sum.getLB()) {
return ESat.FALSE;
}
if (lb == ub && sum.isInstantiated()) {
return ESat.TRUE;
}
return ESat.UNDEFINED;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("PropBoolSumIncremental(");
for (int i = 0; i < vars.length - 2; i++) {
sb.append(vars[i] + "+");
}
sb.append(vars[vars.length - 2] + ")");
sb.append(" = " + vars[vars.length - 1]);
return sb.toString();
}
@Override
public void duplicate(Solver solver, THashMap<Object, Object> identitymap) {
if (!identitymap.containsKey(this)) {
int size = this.vars.length - 1;
BoolVar[] aVars = new BoolVar[size];
for (int i = 0; i < size; i++) {
this.vars[i].duplicate(solver, identitymap);
aVars[i] = (BoolVar) identitymap.get(this.vars[i]);
}
this.vars[size].duplicate(solver, identitymap);
IntVar S = (IntVar) identitymap.get(this.vars[size]);
identitymap.put(this, new PropBoolSumIncremental(aVars, S));
}
}
}