/**
* Copyright (c) 1999-2014, Ecole des Mines de Nantes
* All rights reserved.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the Ecole des Mines de Nantes nor the
* 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
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package solver.constraints.nary.min_max;
import gnu.trove.map.hash.THashMap;
import memory.IStateInt;
import solver.Solver;
import solver.constraints.Propagator;
import solver.constraints.PropagatorPriority;
import solver.exception.ContradictionException;
import solver.variables.BoolVar;
import util.ESat;
import util.tools.ArrayUtils;
/**
* <br/>
*
* @Jean-Guillaume Fages
* @since 15/12/2013
*/
public class PropBoolMax extends Propagator<BoolVar> {
final int n;
final IStateInt x1, x2;
public PropBoolMax(BoolVar[] variables, BoolVar maxVar) {
super(ArrayUtils.append(variables, new BoolVar[]{maxVar}), PropagatorPriority.UNARY, true);
n = variables.length;
x1 = solver.getEnvironment().makeInt(-1);
x2 = solver.getEnvironment().makeInt(-1);
assert n > 0;
}
@Override
public void propagate(int evtmask) throws ContradictionException {
x1.set(-1);
x2.set(-1);
for (int i = 0; i < n; i++) {
if (!vars[i].isInstantiated()) {
if (x1.get() == -1) {
x1.set(i);
} else if (x2.get() == -1) {
x2.set(i);
}
} else if (vars[i].getValue() == 1) {
if (vars[n].instantiateTo(1, aCause)) {
setPassive();
return;
}
}
}
filter();
}
public void propagate(int idxVarInProp, int mask) throws ContradictionException {
if (idxVarInProp == n) {
filter();
} else {
if (vars[idxVarInProp].isInstantiatedTo(1)) {
if (vars[n].instantiateTo(1, aCause)) {
setPassive();
return;
}
} else if (idxVarInProp == x1.get() || idxVarInProp == x2.get()) {
if (idxVarInProp == x1.get()) {
x1.set(x2.get());
}
x2.set(-1);
for (int i = 0; i < n; i++) {
if (i != x1.get() && !vars[i].isInstantiated()) {
x2.set(i);
break;
}
}
filter();
}
}
}
public void filter() throws ContradictionException {
if (x1.get() == -1) {
if (vars[n].instantiateTo(0, aCause)) {
setPassive();
return;
}
}
if (x2.get() == -1 && vars[n].isInstantiatedTo(1)) {
if (vars[x1.get()].instantiateTo(1, aCause)) {
setPassive();
return;
}
}
if (vars[n].isInstantiatedTo(0)) {
for (int i = 0; i < n; i++) {
vars[i].instantiateTo(0, aCause);
}
}
}
@Override
public ESat isEntailed() {
int ub = vars[n].getUB();
for (int i = 0; i < n; i++) {
if (vars[i].getLB() > ub) {
return ESat.FALSE;
}
}
for (int i = 0; i < n; i++) {
if (vars[i].getUB() > ub) {
return ESat.UNDEFINED;
}
}
if (vars[n].isInstantiated()) {
for (int i = 0; i < n; i++) {
if (vars[i].isInstantiatedTo(ub)) {
return ESat.TRUE;
}
}
}
return ESat.UNDEFINED;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder("PropBoolMin ");
sb.append(vars[n]).append(" = min({");
sb.append(vars[0]);
for (int i = 1; i < n; i++) {
sb.append(", ");
sb.append(vars[i]);
}
sb.append("})");
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);
BoolVar M = (BoolVar) identitymap.get(this.vars[size]);
identitymap.put(this, new PropBoolMax(aVars, M));
}
}
}