/**
* 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;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* Created by IntelliJ IDEA.
* User: Jean-Guillaume Fages
* Date: 14/01/13
* Time: 16:36
*/
package solver.constraints.set;
import gnu.trove.list.array.TIntArrayList;
import gnu.trove.map.hash.THashMap;
import solver.Solver;
import solver.constraints.Propagator;
import solver.constraints.PropagatorPriority;
import solver.exception.ContradictionException;
import solver.variables.IntVar;
import solver.variables.SetVar;
import solver.variables.Variable;
import util.ESat;
import util.tools.ArrayUtils;
/**
* Propagator for element constraint over sets
* states that
* array[index-offSet] = set
*
* @author Jean-Guillaume Fages
*/
public class PropElement extends Propagator<Variable> {
//***********************************************************************************
// VARIABLES
//***********************************************************************************
private TIntArrayList constructiveDisjunction;
private IntVar index;
private SetVar set;
private SetVar[] array;
private int offSet;
//***********************************************************************************
// CONSTRUCTORS
//***********************************************************************************
/**
* Propagator for element constraint over sets
* states that array[index-offSet] = set
*
* @param index
* @param array
* @param offSet
* @param set
*/
public PropElement(IntVar index, SetVar[] array, int offSet, SetVar set) {
super(ArrayUtils.append(array, new Variable[]{set, index}), PropagatorPriority.LINEAR, false);
this.index = (IntVar) vars[vars.length - 1];
this.set = (SetVar) vars[vars.length - 2];
this.array = new SetVar[array.length];
for (int i = 0; i < array.length; i++) {
this.array[i] = (SetVar) vars[i];
}
this.offSet = offSet;
constructiveDisjunction = new TIntArrayList();
}
//***********************************************************************************
// METHODS
//***********************************************************************************
@Override
public void propagate(int evtmask) throws ContradictionException {
index.updateLowerBound(offSet, aCause);
index.updateUpperBound(array.length - 1 + offSet, aCause);
if (index.isInstantiated()) {
// filter set and array
setEq(set, array[index.getValue() - offSet]);
setEq(array[index.getValue() - offSet], set);
} else {
// filter index
int ub = index.getUB();
boolean noEmptyKer = true;
for (int i = index.getLB(); i <= ub; i = index.nextValue(i)) {
if (disjoint(set, array[i - offSet]) || disjoint(array[i - offSet], set)) {// array[i] != set
index.removeValue(i, aCause);
} else {
if (array[i - offSet].getKernelSize() == 0) {
noEmptyKer = false;
}
}
}
ub = index.getUB();
// filter set (constructive disjunction)
if (noEmptyKer) {// from ker
constructiveDisjunction.clear();
SetVar v = array[index.getLB() - offSet];
for (int j = v.getKernelFirst(); j != SetVar.END; j = v.getKernelNext()) {
if (!set.kernelContains(j)) {
constructiveDisjunction.add(j);
}
}
for (int cd = constructiveDisjunction.size() - 1; cd >= 0; cd--) {
int j = constructiveDisjunction.get(cd);
for (int i = index.nextValue(index.getLB()); i <= ub; i = index.nextValue(i)) {
if (!array[i - offSet].kernelContains(j)) {
constructiveDisjunction.remove(j);
break;
}
}
}
for (int cd = constructiveDisjunction.size() - 1; cd >= 0; cd--) {
int j = constructiveDisjunction.get(cd);
set.addToKernel(j, aCause);
}
}
if (!set.isInstantiated()) {// from env
for (int j = set.getEnvelopeFirst(); j != SetVar.END; j = set.getEnvelopeNext()) {
boolean valueExists = false;
for (int i = index.getLB(); i <= ub; i = index.nextValue(i)) {
if (array[i - offSet].envelopeContains(j)) {
valueExists = true;
break;
}
}
if (!valueExists) {
set.removeFromEnvelope(j, aCause);
}
}
}
}
}
private void setEq(SetVar s1, SetVar s2) throws ContradictionException {
for (int j = s2.getKernelFirst(); j != SetVar.END; j = s2.getKernelNext()) {
s1.addToKernel(j, aCause);
}
for (int j = s1.getEnvelopeFirst(); j != SetVar.END; j = s1.getEnvelopeNext()) {
if (!s2.envelopeContains(j)) {
s1.removeFromEnvelope(j, aCause);
}
}
}
private boolean disjoint(SetVar s1, SetVar s2) {
for (int j = s2.getKernelFirst(); j != SetVar.END; j = s2.getKernelNext()) {
if (!s1.envelopeContains(j)) {
return true;
}
}
return false;
}
@Override
public ESat isEntailed() {
if (index.isInstantiated()) {
if (disjoint(set, array[index.getValue() - offSet]) || disjoint(array[index.getValue() - offSet], set)) {
return ESat.FALSE;
} else {
if (set.isInstantiated() && array[index.getValue() - offSet].isInstantiated()) {
return ESat.TRUE;
} else {
return ESat.UNDEFINED;
}
}
}
return ESat.UNDEFINED;
}
@Override
public void duplicate(Solver solver, THashMap<Object, Object> identitymap) {
if (!identitymap.containsKey(this)) {
int size = this.vars.length - 2;
SetVar[] aVars = new SetVar[size];
for (int i = 0; i < size; i++) {
this.vars[i].duplicate(solver, identitymap);
aVars[i] = (SetVar) identitymap.get(this.vars[i]);
}
set.duplicate(solver, identitymap);
SetVar S = (SetVar) identitymap.get(set);
index.duplicate(solver, identitymap);
IntVar I = (IntVar) identitymap.get(index);
identitymap.put(this, new PropElement(I, aVars, offSet, S));
}
}
}