org.chocosolver.solver.expression.discrete.logical.LoExpression Maven / Gradle / Ivy
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/*
* 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.expression.discrete.logical;
import org.chocosolver.solver.Model;
import org.chocosolver.solver.expression.discrete.relational.ReExpression;
import org.chocosolver.solver.variables.BoolVar;
/**
*
* Project: choco-solver.
*
* @author Charles Prud'homme
* @since 04/04/2017.
*/
public abstract class LoExpression implements ReExpression {
/**
* List of available operator for relational expression
*/
public enum Operator {
/**
* less than
*/
AND {
@Override
boolean eval(boolean b1, boolean b2) {
return b1 && b2;
}
},
/**
* less than or equal to
*/
OR {
@Override
boolean eval(boolean b1, boolean b2) {
return b1 || b2;
}
},
XOR{
@Override
boolean eval(boolean b1, boolean b2) {
return b1 != b2;
}
},
IFF{
@Override
boolean eval(boolean b1, boolean b2) {
return b1 == b2;
}
},
IMP{
@Override
boolean eval(boolean b1, boolean b2) {
return !b1 || b2;
}
},
NOT{
@Override
boolean eval(boolean b1, boolean b2) {
return !b1 || !b2;
}
};
abstract boolean eval(boolean b1, boolean b2);
}
/**
* The model in which the expression is declared
*/
protected final Model model;
/**
* Lazy creation of the underlying variable
*/
protected BoolVar me = null;
/**
* Operator of the arithmetic expression
*/
protected final Operator op;
public LoExpression(Model model, Operator op) {
this.model = model;
this.op = op;
}
/**
* Return the associated model
*
* @return a Model object
*/
public abstract Model getModel();
/**
* @return the logical expression as an {@link BoolVar}.
* If necessary, it creates intermediary variable and posts intermediary constraints
*/
public abstract BoolVar boolVar();
}