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Open-source constraint solver.
/*
* This file is part of choco-solver, http://choco-solver.org/
*
* Copyright (c) 2022, 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.real;
import org.chocosolver.solver.constraints.Propagator;
import org.chocosolver.solver.constraints.PropagatorPriority;
import org.chocosolver.solver.exception.ContradictionException;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.solver.variables.RealVar;
import org.chocosolver.solver.variables.Variable;
import org.chocosolver.util.ESat;
/**
* A propagator that ensures that a real variable X is equal to an integer variable Y.
*
*
* @author Charles Prud'homme
* @since 24/01/2020
*/
public class PropMixed extends Propagator {
RealVar x;
IntVar y;
public PropMixed(RealVar x, IntVar y) {
super(new Variable[]{x, y}, PropagatorPriority.BINARY, false);
this.x = x;
this.y = y;
}
@Override
public void propagate(int evtmask) throws ContradictionException {
y.updateLowerBound((int) Math.ceil(x.getLB()), this);
y.updateUpperBound((int) Math.floor(x.getUB()), this);
x.intersect(y.getLB(), y.getUB(), this);
}
@Override
public ESat isEntailed() {
if(isCompletelyInstantiated()) {
return ESat.eval(y.getLB() <= x.getUB() && x.getLB() <= y.getUB());
}
return ESat.UNDEFINED;
}
}