org.chocosolver.solver.variables.RealVar Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of choco-solver Show documentation
Open-source constraint solver.
There is a newer version: 4.10.17
/*
 * This file is part of choco-solver, http://choco-solver.org/
 *
 * Copyright (c) 2019, 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.variables;

import org.chocosolver.solver.ICause;
import org.chocosolver.solver.exception.ContradictionException;
import org.chocosolver.solver.expression.continuous.arithmetic.CArExpression;

/**
 * An interface to declare variable for continuous constraints (solved using IBEX).
 * 

 *
 * @author Charles Prud'homme
 * @since 18/07/12
 */
public interface RealVar extends Variable, CArExpression {

    /**
     * Retrieves the lower bound of the variable
     *
     * @return the lower bound
     */
    double getLB();

    /**
     * Retrieves the upper bound of the variable
     *
     * @return the upper bound
     */
    double getUB();

    /**
     * Updates the lower bound of the domain of this to value.
     * The instruction comes from propagator.
     * 
     * If value is smaller than the lower bound of the domain, nothing is done and the return value is false,
     * if updating the lower bound to value leads to a dead-end (domain wipe-out),
     * a ContradictionException is thrown,
     * otherwise, if updating the lower bound to value can be done safely,
     * the event type is created (the original event can be promoted) and observers are notified
     * and the return value is true
     * 
     *
     * @param value new lower bound (included)
     * @param cause updating releaser
     * @return true if the lower bound has been updated, false otherwise
     * @throws ContradictionException if the domain become empty due to this action
     */
    boolean updateLowerBound(double value, ICause cause) throws ContradictionException;

    /**
     * Updates the upper bound of the domain of this to value.
     * The instruction comes from propagator.
     * 
     * If value is greater than the upper bound of the domain, nothing is done and the return value is false,
     * if updating the upper bound to value leads to a dead-end (domain wipe-out),
     * a ContradictionException is thrown,
     * otherwise, if updating the upper bound to value can be done safely,
     * the event type is created (the original event can be promoted) and observers are notified
     * and the return value is true
     * 
     *
     * @param value new upper bound (included)
     * @param cause update releaser
     * @return true if the upper bound has been updated, false otherwise
     * @throws org.chocosolver.solver.exception.ContradictionException
     *          if the domain become empty due to this action
     */
    boolean updateUpperBound(double value, ICause cause) throws ContradictionException;

    /**
     * Updates the bounds of the domain of this to value.
     * The instruction comes from propagator.
     * 
     * If the interval defined by [lowerbound,upperbound] includes the domain of this, nothing is done and the return value is false,
     * if updating the domain leads to a dead-end (domain wipe-out),
     * a ContradictionException is thrown,
     * otherwise, if updating the domain be done safely,
     * the event type is created (the original event can be promoted) and observers are notified
     * and the return value is true
     * 
     *
     * @param lowerbound new lower bound (included)
     * @param upperbound new upper bound (included)
     * @param cause      update releaser
     * @return true if the upper bound has been updated, false otherwise
     * @throws org.chocosolver.solver.exception.ContradictionException
     *          if the domain become empty due to this action
     */
    boolean updateBounds(double lowerbound, double upperbound, ICause cause) throws ContradictionException;

    double getPrecision();

    @Override
    default RealVar realVar(double p){
        return this;
    }

}