/**
* 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:
*
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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
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package solver.constraints.nary.cumulative;
import solver.constraints.Propagator;
import solver.exception.ContradictionException;
import solver.variables.IntVar;
import util.objects.setDataStructures.ISet;
import util.sort.ArraySort;
import util.sort.IntComparator;
/**
* Energy based filtering (greedy)
* @author Jean-Guillaume Fages
*/
public class NRJCumulFilter extends CumulFilter{
//***********************************************************************************
// VARIABLES
//***********************************************************************************
protected int[] sor_array;
protected ArraySort sorter;
protected IntComparator comparator;
protected int[] slb, dlb, eub, hlb;
//***********************************************************************************
// CONSTRUCTORS
//***********************************************************************************
public NRJCumulFilter(int n, Propagator cause){
super(n,cause);
sor_array = new int[n];
sorter = new ArraySort(n,false,true);
slb = new int[n];
dlb = new int[n];
eub = new int[n];
hlb = new int[n];
comparator = new IntComparator(){
@Override
public int compare(int i1, int i2) {
int coef1 = (100*dlb[i1]*hlb[i1])/(eub[i1]-slb[i1]);
int coef2 = (100*dlb[i2]*hlb[i2])/(eub[i2]-slb[i2]);
return coef2 - coef1;
}
};
}
//***********************************************************************************
// METHODS
//***********************************************************************************
@Override
public void filter(IntVar[] s, IntVar[] d, IntVar[] e, IntVar[] h, IntVar capa, ISet tasks) throws ContradictionException {
int idx = 0;
for (int i = tasks.getFirstElement(); i >= 0; i = tasks.getNextElement()) {
if(d[i].getLB()>0){
slb[i] = s[i].getLB();
dlb[i] = d[i].getLB();
eub[i] = e[i].getUB();
hlb[i] = h[i].getLB();
assert eub[i]>slb[i];
sor_array[idx++] = i;
}
}
sorter.sort(sor_array,idx,comparator);
double xMin = Integer.MAX_VALUE / 2;
double xMax = Integer.MIN_VALUE / 2;
double surface = 0;
double camax = capa.getUB();
for(int k=0; k<idx; k++){
int i = sor_array[k];
xMax = Math.max(xMax, eub[i]);
xMin = Math.min(xMin, slb[i]);
if(xMax >= xMin){
double availSurf = ((xMax-xMin)*camax-surface);
if(dlb[i]>0)
h[i].updateUpperBound((int)Math.floor((availSurf/(double)dlb[i])+0.01),aCause);
if(hlb[i]>0)
d[i].updateUpperBound((int)Math.floor((availSurf/(double)hlb[i])+0.01),aCause);
surface += dlb[i] * hlb[i];
if(xMax>xMin){
capa.updateLowerBound((int)Math.ceil(surface/(xMax-xMin)-0.01),aCause);
}if(surface>(xMax-xMin)*camax){
aCause.contradiction(capa,"");
}
}
}
}
}