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Open-source constraint solver.
/*
* This file is part of choco-solver, http://choco-solver.org/
*
* Copyright (c) 2020, IMT Atlantique. All rights reserved.
*
* Licensed under the BSD 4-clause license.
*
* See LICENSE file in the project root for full license information.
*/
package org.chocosolver.solver.constraints.extension.nary;
import org.chocosolver.memory.IEnvironment;
import org.chocosolver.memory.IStateInt;
import org.chocosolver.solver.constraints.extension.Tuples;
import org.chocosolver.solver.exception.ContradictionException;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.util.iterators.DisposableValueIterator;
import org.chocosolver.util.objects.setDataStructures.iterable.IntIterableBitSet;
/**
*
*
* @author Charles Prud'homme
* @since 26/07/12
*/
public class PropLargeGAC2001Positive extends PropLargeCSP {
/**
* supports[i][j stores the index of the tuple that currently support
* the variable-value pair (i,j)
*/
private IStateInt[][] supports;
private int arity;
private int[] offsets;
private static final int NO_SUPPORT = -2;
private int[][][] tab;
// check if none of the tuple is trivially outside
//the domains and if yes use a fast valid check
//by avoiding checking the bounds
private ValidityChecker valcheck;
private final IntIterableBitSet vrms;
private PropLargeGAC2001Positive(IntVar[] vs, IterTuplesTable relation) {
super(vs, relation);
this.arity = vs.length;
this.offsets = new int[arity];
this.supports = new IStateInt[arity][];
IEnvironment environment = model.getEnvironment();
for (int i = 0; i < arity; i++) {
offsets[i] = vs[i].getLB();
this.supports[i] = new IStateInt[vars[i].getRange()];
for (int j = 0; j < supports[i].length; j++) {
this.supports[i][j] = environment.makeInt(0);
}
}
this.tab = relation.getTableLists();
int[][] tt = relation.getTupleTable();
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
loop:
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]) {
}
if (lb < 0 || ub > 1) {
fastBooleanValidCheckAllowed = false;
break loop;
}
}
}
if (fastBooleanValidCheckAllowed) {
valcheck = new FastBooleanValidityChecker(arity, vars);
} else valcheck = new ValidityChecker(arity, vars);
vrms = new IntIterableBitSet();
}
public PropLargeGAC2001Positive(IntVar[] vs, Tuples tuples) {
this(vs, RelationFactory.makeIterableRelation(tuples, vs));
}
@Override
public void propagate(int evtmask) throws ContradictionException {
for (int indexVar = 0; indexVar < arity; indexVar++) {
reviseVar(indexVar);
}
}
@Override
public void propagate(int idxVarInProp, int mask) throws ContradictionException {
filter(idxVarInProp);
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/**
* updates the support for all values in the domain of variable
* and remove unsupported values for variable
*
* @throws ContradictionException
*/
private void reviseVar(int indexVar) throws ContradictionException {
DisposableValueIterator itv = vars[indexVar].getValueIterator(true);
vrms.clear();
vrms.setOffset(vars[indexVar].getLB());
try {
while (itv.hasNext()) {
int val = itv.next();
int nva = val - relation.getRelationOffset(indexVar);
int currentIdxSupport = getUBport(indexVar, val);
currentIdxSupport = seekNextSupport(indexVar, nva, currentIdxSupport);
if (currentIdxSupport == NO_SUPPORT) {
vrms.add(val);
// vars[indexVar].removeVal(val, this, false);
} else {
setSupport(indexVar, val, currentIdxSupport);
}
}
vars[indexVar].removeValues(vrms, this);
} finally {
itv.dispose();
}
}
/**
* seek a new support for the pair variable-value : (indexVar, nva)
* start the iteration from the stored support (the last one)
*/
private int seekNextSupport(int indexVar, int nva, int start) {
int currentIdxSupport;
int[] currentSupport;
for (int i = start; i < tab[indexVar][nva].length; i++) {
currentIdxSupport = tab[indexVar][nva][i];
currentSupport = relation.getTuple(currentIdxSupport);
if (valcheck.isValid(currentSupport)) return i;
}
return NO_SUPPORT;
}
/**
* store the new support
*
* @param idxSupport : the index of the support in the list of allowed tuples for
* the pair variable-value (indexVar,value)
*/
private void setSupport(int indexVar, int value, int idxSupport) {
supports[indexVar][value - offsets[indexVar]].set(idxSupport); //- offset already included in blocks
}
/**
* @return the stored support for the pair (indexVar,value)
*/
private int getUBport(int indexVar, int value) {
return supports[indexVar][value - offsets[indexVar]].get();
}
private void filter(int idx) throws ContradictionException {
//sort variables regarding domain sizes to speedup the check !
valcheck.sortvars();
for (int i = 0; i < arity; i++)
if (idx != valcheck.getPosition(i)) reviseVar(valcheck.getPosition(i));
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("GAC2001AllowedLarge({");
for (int i = 0; i < vars.length; i++) {
if (i > 0) sb.append(", ");
IntVar var = vars[i];
sb.append(var);
}
sb.append("})");
return sb.toString();
}
}