/**
* Copyright (c) 1999-2014, Ecole des Mines de Nantes
* All rights reserved.
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* 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
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*/
package solver.constraints.extension.binary;
import gnu.trove.map.hash.THashMap;
import solver.Solver;
import solver.constraints.extension.Tuples;
import solver.exception.ContradictionException;
import solver.variables.IntVar;
import solver.variables.events.IntEventType;
import solver.variables.events.PropagatorEventType;
import util.iterators.DisposableValueIterator;
/**
* AC3 bit rm algorithm for binary table constraint
* <br/>
*
* @author Charles Prud'homme, Hadrien Cambazard
* @since 22/04/2014
*/
public class PropBinAC3bitrm extends PropBinCSP {
protected int offset0;
protected int offset1;
protected int minS0; //value with minimum number of supports for v0
protected int minS1; //value with minimum number of supports for v1
protected int initDomSize0;
protected int initDomSize1;
public PropBinAC3bitrm(IntVar x, IntVar y, Tuples tuples) {
this(x, y, new CouplesBitSetTable(tuples, x, y));
}
private PropBinAC3bitrm(IntVar x, IntVar y, CouplesBitSetTable table) {
super(x, y, table);
}
@Override
public void propagate(int evtmask) throws ContradictionException {
if (PropagatorEventType.isFullPropagation(evtmask)) {
offset0 = v0.getLB();
offset1 = v1.getLB();
initDomSize0 = v0.getDomainSize();
initDomSize1 = v1.getDomainSize();
fastInitNbSupports();
int left = Integer.MIN_VALUE;
int right = left;
DisposableValueIterator itv0 = v0.getValueIterator(true);
try {
while (itv0.hasNext()) {
int val0 = itv0.next();
if (!((CouplesBitSetTable) relation).checkValue(0, val0, v1)) {
if (val0 == right + 1) {
right = val0;
} else {
v0.removeInterval(left, right, this);
left = right = val0;
}
}
}
v0.removeInterval(left, right, this);
} finally {
itv0.dispose();
}
itv0 = v1.getValueIterator(true);
left = right = Integer.MIN_VALUE;
try {
while (itv0.hasNext()) {
int val1 = itv0.next();
if (!((CouplesBitSetTable) relation).checkValue(1, val1, v0)) {
if (val1 == right + 1) {
right = val1;
} else {
v1.removeInterval(left, right, this);
left = right = val1;
}
}
}
v1.removeInterval(left, right, this);
} finally {
itv0.dispose();
}
}
reviseV0();
reviseV1();
}
@Override
public void propagate(int idxVarInProp, int mask) throws ContradictionException {
if (IntEventType.isInstantiate(mask)) {
onInstantiationOf(idxVarInProp);
} else if (idxVarInProp == 0) {
reviseV1();
} else {
reviseV0();
}
}
@Override
public void duplicate(Solver solver, THashMap<Object, Object> identitymap) {
if (!identitymap.containsKey(this)) {
this.vars[0].duplicate(solver, identitymap);
IntVar X = (IntVar) identitymap.get(this.vars[0]);
this.vars[1].duplicate(solver, identitymap);
IntVar Y = (IntVar) identitymap.get(this.vars[1]);
identitymap.put(this, new PropBinAC3bitrm(X, Y, (CouplesBitSetTable) relation.duplicate()));
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
private void fastInitNbSupports() {
int[] initS1 = new int[v1.getUB() - v1.getLB() + 1];
minS0 = Integer.MAX_VALUE;
minS1 = Integer.MAX_VALUE;
DisposableValueIterator itv0 = v0.getValueIterator(true);
while (itv0.hasNext()) {
int val0 = itv0.next();
int initS0 = 0;
DisposableValueIterator itv1 = v1.getValueIterator(true);
while (itv1.hasNext()) {
int val1 = itv1.next();
if (relation.isConsistent(val0, val1)) {
initS0++;
initS1[val1 - offset1]++;
}
}
if (initS0 < minS0) minS0 = initS0;
itv1.dispose();
}
itv0.dispose();
for (int i = 0; i < initS1.length; i++) {
if (initS1[i] < minS1) minS1 = initS1[i];
}
}
/**
* updates the support for all values in the domain of v1, and remove unsupported values for v1
*/
private void reviseV1() throws ContradictionException {
int v0Size = v0.getDomainSize();
if (minS1 <= (initDomSize0 - v0Size)) {
int left = Integer.MIN_VALUE;
int right = left;
DisposableValueIterator itv1 = v1.getValueIterator(true);
try {
while (itv1.hasNext()) {
int y = itv1.next();
if (!((CouplesBitSetTable) relation).checkValue(1, y, v0)) {
if (y == right + 1) {
right = y;
} else {
v1.removeInterval(left, right, this);
left = right = y;
}
// v1.removeVal(y, this, false);
}
}
v1.removeInterval(left, right, this);
} finally {
itv1.dispose();
}
}
}
/**
* updates the support for all values in the domain of v0, and remove unsupported values for v0
*/
private void reviseV0() throws ContradictionException {
int v1Size = v1.getDomainSize();
if (minS0 <= (initDomSize1 - v1Size)) {
int left = Integer.MIN_VALUE;
int right = left;
DisposableValueIterator itv0 = v0.getValueIterator(true);
try {
while (itv0.hasNext()) {
int x = itv0.next();
if (!((CouplesBitSetTable) relation).checkValue(0, x, v1)) {
if (x == right + 1) {
right = x;
} else {
v0.removeInterval(left, right, this);
left = right = x;
}
// v0.removeVal(x, this, false);
}
}
v0.removeInterval(left, right, this);
} finally {
itv0.dispose();
}
}
}
private void onInstantiationOf(int idx) throws ContradictionException {
if (idx == 0) {
int value = v0.getValue();
int left = Integer.MIN_VALUE;
int right = left;
DisposableValueIterator itv1 = v1.getValueIterator(true);
try {
while (itv1.hasNext()) {
int val = itv1.next();
if (!relation.isConsistent(value, val)) {
if (val == right + 1) {
right = val;
} else {
v1.removeInterval(left, right, this);
left = right = val;
}
}
}
v1.removeInterval(left, right, this);
} finally {
itv1.dispose();
}
} else {
int value = v1.getValue();
int left = Integer.MIN_VALUE;
int right = left;
DisposableValueIterator itv0 = v0.getValueIterator(true);
try {
while (itv0.hasNext()) {
int val = itv0.next();
if (!relation.isConsistent(val, value)) {
if (val == right + 1) {
right = val;
} else {
v0.removeInterval(left, right, this);
left = right = val;
}
}
}
v0.removeInterval(left, right, this);
} finally {
itv0.dispose();
}
}
}
}