/**
* 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
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* * 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.
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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
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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package solver.constraints.extension.nary;
import gnu.trove.list.TIntList;
import gnu.trove.list.linked.TIntLinkedList;
import gnu.trove.map.hash.THashMap;
import memory.IStateInt;
import solver.Solver;
import solver.constraints.extension.Tuples;
import solver.exception.ContradictionException;
import solver.variables.IntVar;
import util.iterators.DisposableValueIterator;
import java.util.BitSet;
/**
* GAC maintaind by STR
* <br/>
*
* @author Charles Prud'homme, Hadrien Cambazard
* @since 24/04/2014
*/
public class PropLargeGACSTRPos extends PropLargeCSP<TuplesList> {
// check if none of the tuple is trivially outside
// the domains and if yes use a fast valid check
// by avoiding checking the bounds
protected ValidityChecker valcheck;
/**
* size of the scope
*/
protected int arity;
/**
* original lower bounds
*/
protected int[] offsets;
/**
* Variables that are not proved to be GAC yet
*/
protected TIntList futureVars;
/**
* Values that have found a support for each variable
*/
protected BitSet[] gacValues;
protected int[] nbGacValues;
/**
* The backtrackable list of tuples representing the current
* allowed tuples of the constraint
*/
protected IStateInt last;
int[] listuples;
private PropLargeGACSTRPos(IntVar[] vs, TuplesList relation) {
super(vs, relation);
this.arity = vs.length;
this.futureVars = new TIntLinkedList();
this.gacValues = new BitSet[arity];
this.nbGacValues = new int[arity];
this.offsets = new int[arity];
for (int i = 0; i < arity; i++) {
this.offsets[i] = vs[i].getLB();
this.gacValues[i] = new BitSet(vs[i].getDomainSize());
}
listuples = new int[this.relation.getTupleTable().length];
for (int i = 0; i < listuples.length; i++) {
listuples[i] = i;
}
last = solver.getEnvironment().makeInt(listuples.length - 1);
int[][] tt = this.relation.getTupleTable();
boolean fastValidCheckAllowed = true;
boolean fastBooleanValidCheckAllowed = true;
// check if all tuples are within the range
// of the domain and if so set up a faster validity checker
// that avoids checking original bounds first
for (int i = 0; i < tt.length; i++) {
for (int j = 0; j < tt[i].length; j++) {
int lb = vs[j].getLB();
int ub = vs[j].getUB();
if (lb > tt[i][j] ||
ub < tt[i][j]) {
fastValidCheckAllowed = false;
}
if (lb < 0 || ub > 1) {
fastBooleanValidCheckAllowed = false;
}
}
if (!fastBooleanValidCheckAllowed &&
!fastValidCheckAllowed) break;
}
if (fastBooleanValidCheckAllowed) {
valcheck = new FastBooleanValidityChecker(arity, vars);
} else if (fastValidCheckAllowed) {
valcheck = new FastValidityChecker(arity, vars);
} else valcheck = new ValidityChecker(arity, vars);
}
public PropLargeGACSTRPos(IntVar[] vs, Tuples tuples) {
this(vs, makeRelation(tuples, vs));
}
private static TuplesList makeRelation(Tuples tuples, IntVar[] vars) {
return new TuplesList(tuples, vars);
}
@Override
public void propagate(int evtmask) throws ContradictionException {
valcheck.sortvars();
gacstr();
}
@Override
public void propagate(int idxVarInProp, int mask) throws ContradictionException {
filter(idxVarInProp);
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
public void initializeData() {
//INITIALIZATION
futureVars.clear();
for (int i = 0; i < arity; i++) {
gacValues[i].clear();
nbGacValues[i] = 0;
futureVars.add(i);
}
}
public void pruningPhase() throws ContradictionException {
for (int i = 0; i < futureVars.size(); i++) {
int vIdx = futureVars.get(i);
IntVar v = vars[vIdx];
DisposableValueIterator it3 = v.getValueIterator(true);
int left = Integer.MIN_VALUE;
int right = left;
try {
while (it3.hasNext()) {
int val = it3.next();
if (!gacValues[vIdx].get(val - offsets[vIdx])) {
if (val == right + 1) {
right = val;
} else {
v.removeInterval(left, right, this);
left = right = val;
}
// v.removeVal(val, this, false);
}
}
v.removeInterval(left, right, this);
} finally {
it3.dispose();
}
}
}
/**
* maintain the list by checking all variable within isValid
*/
//maintain the list by checking only the variable that has changed when
//* checking if a tuple is valid.
//*
//* @param idx : the variable changed
public void maintainList(/*int idx*/) {
int cidx = 0;
int nLast = last.get();
while (cidx <= nLast) {
int idxt = listuples[cidx++];
int[] tuple = relation.getTuple(idxt);
if (valcheck.isValid(tuple/*,idx*/)) {
//extract the supports
for (int i = 0; i < futureVars.size(); i++) {
int vIdx = futureVars.get(i);
if (!gacValues[vIdx].get(tuple[vIdx] - offsets[vIdx])) {
gacValues[vIdx].set(tuple[vIdx] - offsets[vIdx]);
nbGacValues[vIdx]++;
if (nbGacValues[vIdx] == vars[vIdx].getDomainSize()) {
futureVars.removeAt(i);
i--;
}
}
}
} else {
//remove the tuple from the current list
cidx--;
final int temp = listuples[nLast];
listuples[nLast] = listuples[cidx];
listuples[cidx] = temp;
last.add(-1);
nLast--;
}
}
}
/**
* Main propagation loop. It maintains the list of valid tuples
* through the search
*
* @throws ContradictionException
*/
public void gacstr() throws ContradictionException {
initializeData();
maintainList();
pruningPhase();
if (getCartesianProduct() <= last.get() + 1) {
setPassive();
}
}
public double getCartesianProduct() {
double cp = 1d;
for (int i = 0; i < arity; i++) {
cp *= vars[i].getDomainSize();
}
return cp;
}
public void filter(int idx) throws ContradictionException {
//sort variables regarding domain sizes to speedup the check !
valcheck.sortvars();
gacstr();
//constAwake(false);
}
@Override
public void duplicate(Solver solver, THashMap<Object, Object> identitymap) {
if (!identitymap.containsKey(this)) {
int size = this.vars.length;
IntVar[] aVars = new IntVar[size];
for (int i = 0; i < size; i++) {
this.vars[i].duplicate(solver, identitymap);
aVars[i] = (IntVar) identitymap.get(this.vars[i]);
}
identitymap.put(this, new PropLargeGACSTRPos(aVars, (TuplesList) relation.duplicate()));
}
}
}