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Open-source constraint solver.
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/*
* This file is part of choco-solver, http://choco-solver.org/
*
* Copyright (c) 2024, 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.nary.cumulative;
import org.chocosolver.memory.IStateInt;
import org.chocosolver.solver.constraints.Propagator;
import org.chocosolver.solver.constraints.PropagatorPriority;
import org.chocosolver.solver.exception.ContradictionException;
import org.chocosolver.solver.learn.ExplanationForSignedClause;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.solver.variables.events.IntEventType;
import org.chocosolver.solver.variables.events.PropagatorEventType;
import org.chocosolver.util.ESat;
import org.chocosolver.util.objects.setDataStructures.ISet;
import org.chocosolver.util.objects.setDataStructures.ISetIterator;
import org.chocosolver.util.objects.setDataStructures.SetFactory;
import org.chocosolver.util.objects.setDataStructures.SetType;
import org.chocosolver.util.objects.setDataStructures.iterable.IntIterableRangeSet;
import org.chocosolver.util.tools.ArrayUtils;
import java.util.Arrays;
import java.util.stream.IntStream;
/**
* Cumulative propagator
* Performs energy checking and mandatory part based filtering
* BEWARE : not idempotent, use two propagators to get the fix point
*
* @author Jean-Guillaume Fages
* @since 31/01/13
*/
public class PropCumulative extends Propagator {
//***********************************************************************************
// VARIABLES
//***********************************************************************************
protected final int n;
protected final IntVar[] s, d, e, h;
protected final IntVar capa;
protected CumulFilter[] filters;
protected ISet allTasks;
protected final IStateInt lastCapaMax;
//***********************************************************************************
// CONSTRUCTORS
//***********************************************************************************
/**
* protected constructor, should not be called by a user
*/
protected PropCumulative(IntVar[] s, IntVar[] d, IntVar[] e, IntVar[] h, IntVar capa,
boolean reactToFineEvt, CumulFilter... filters) {
super(ArrayUtils.append(s, d, e, h, new IntVar[]{capa}), PropagatorPriority.QUADRATIC, reactToFineEvt);
this.n = s.length;
if (!(n == d.length && n == e.length && n == h.length)) {
throw new UnsupportedOperationException();
}
this.s = Arrays.copyOfRange(vars, 0, n);
this.d = Arrays.copyOfRange(vars, n, n * 2);
this.e = Arrays.copyOfRange(vars, n * 2, n * 3);
this.h = Arrays.copyOfRange(vars, n * 3, n * 4);
this.capa = this.vars[4 * n];
this.filters = filters;
lastCapaMax = model.getEnvironment().makeInt(capa.getUB() + 1);
allTasks = SetFactory.makeStoredSet(SetType.BIPARTITESET,0,getModel());
for(int t=0;t0) {
h[i].updateUpperBound(capaMax, this);
}else if(h[i].getLB()>capaMax){
d[i].instantiateTo(0,this);
}
}
}
}
public void filter(ISet tasks) throws ContradictionException {
ISetIterator tIter = tasks.iterator();
while (tIter.hasNext()){
int t = tIter.nextInt();
if(h[t].getUB()==0 || d[t].getUB()==0){
tasks.remove(t);
}
}
for (CumulFilter cf : filters) {
cf.filter(s, d, e, h, capa, tasks, this);
}
}
@Override
public ESat isEntailed() {
int min = s[0].getUB();
int max = e[0].getLB();
// check start + duration = end
for (int i = 0; i < n; i++) {
min = Math.min(min, s[i].getUB());
max = Math.max(max, e[i].getLB());
if (s[i].getLB() + d[i].getLB() > e[i].getUB()
|| s[i].getUB() + d[i].getUB() < e[i].getLB()) {
return ESat.FALSE;
}
}
// check capacity
int maxLoad = 0;
if (min <= max) {
int capamax = capa.getUB();
int[] consoMin = new int[max - min];
for (int i = 0; i < n; i++) {
for (int t = s[i].getUB(); t < e[i].getLB(); t++) {
consoMin[t - min] += h[i].getLB();
if (consoMin[t - min] > capamax) {
return ESat.FALSE;
}
maxLoad = Math.max(maxLoad, consoMin[t - min]);
}
}
}
// check variables are instantiated
for (int i = 0; i < vars.length - 1; i++) {
if (!vars[i].isInstantiated()) {
return ESat.UNDEFINED;
}
}
assert min <= max;
// capacity check entailed
if (maxLoad <= vars[4 * n].getLB()) {
return ESat.TRUE;
}
// capacity not instantiated
return ESat.UNDEFINED;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder(this.getClass().getSimpleName() + "(");
for (int i = 0; i < n; i++) {
sb.append("[").append(vars[i].toString());
sb.append(",").append(vars[i + n].toString());
sb.append(",").append(vars[i + 2 * n].toString());
sb.append(",").append(vars[i + 3 * n].toString()).append("],");
}
sb.append(vars[4 * n].toString()).append(")");
return sb.toString();
}
/**
* Return the index of an IntVar
*
* @param pivot variable
*/
private int getInd(IntVar pivot) {
int ind = -1;
for (int i = 0; i < vars.length; i++) {
if (vars[i] == pivot) {
ind = i;
}
}
if (ind == -1) throw new UnsupportedOperationException("pivot variable cannot be found");
return ind;
}
private boolean explainOverlap(ExplanationForSignedClause e, int[] indexes, int t, int[] indD) {
boolean flag = false;
for (int i : indexes) {
if (e.domain(vars[i]).max() < t && e.domain(vars[i]).min() >= t - e.domain(vars[indD[i]]).min()) {
vars[i].unionLit(t, IntIterableRangeSet.MAX, e);
vars[i].unionLit(IntIterableRangeSet.MIN, t - 1 - e.domain(vars[indD[i]]).min(), e);
flag = true;
}
}
return flag;
}
/**
* Detect and explain the event at pivot variable p
*
* @param p pivot variable
*/
@Override
public void explain(int p, ExplanationForSignedClause e) {
IntVar pivot = e.readVar(p);
int[] X = IntStream.range(0, n).filter(i -> vars[i] != pivot).toArray();
int[] indD = IntStream.range(n, n * 2).toArray();
int t = e.readValue(p);
int ipivot = getInd(pivot);
if (ipivot >= n) {
throw new UnsupportedOperationException("Try to explain an event not on a start variable. " +
"Only Cumulative.Filter.NAIVETIME algorithm is currently supported with explanations.");
}
int dpivot = e.domain(vars[ipivot + n]).min();
switch (e.readMask(p)) {
case 2://INCLOW
if (explainOverlap(e, X, t, indD)) {
IntIterableRangeSet set = e.empty();
set.addBetween(t - dpivot, t - 1);
pivot.intersectLit(set.flip(), e);
}else{
throw new UnsupportedOperationException("Unable to find overlapping tasks");
}
break;
case 4://DECUPP
t++;// required due to decomposition
if (explainOverlap(e, X, t + dpivot, indD)) {
IntIterableRangeSet set = e.empty();
set.addBetween(t, t - 1 + dpivot);
pivot.intersectLit(set.flip(), e);
} else {
throw new UnsupportedOperationException("Unable to find overlapping tasks");
}
break;
case 8://INSTANTIATE
case 1://REMOVE
case 0://VOID
case 6://BOUND inclow+decup
default:
throw new UnsupportedOperationException("Unknown event type explanation");
}
}
}