001package net.sf.cpsolver.ifs.criteria;
002
003import java.util.Collection;
004import java.util.Set;
005
006import net.sf.cpsolver.ifs.model.InfoProvider;
007import net.sf.cpsolver.ifs.model.ModelListener;
008import net.sf.cpsolver.ifs.model.Value;
009import net.sf.cpsolver.ifs.model.Variable;
010
011/**
012 * Criterion. <br>
013 * <br>
014 * An optimization objective can be split into several (optimization) criteria
015 * and modeled as a weighted sum of these. This makes the implementation of a particular problem
016 * more versatile as it allows for an easier modification of the optimization objective.
017 * 
018 * @version IFS 1.2 (Iterative Forward Search)<br>
019 *          Copyright (C) 2006 - 2011 Tomáš Müller<br>
020 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
021 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
022 * <br>
023 *          This library is free software; you can redistribute it and/or modify
024 *          it under the terms of the GNU Lesser General Public License as
025 *          published by the Free Software Foundation; either version 3 of the
026 *          License, or (at your option) any later version. <br>
027 * <br>
028 *          This library is distributed in the hope that it will be useful, but
029 *          WITHOUT ANY WARRANTY; without even the implied warranty of
030 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
031 *          Lesser General Public License for more details. <br>
032 * <br>
033 *          You should have received a copy of the GNU Lesser General Public
034 *          License along with this library; if not see
035 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
036 */
037public interface Criterion<V extends Variable<V, T>, T extends Value<V, T>> extends ModelListener<V, T>, InfoProvider<V> {
038    
039    /** Current value of the criterion (optimization objective) */
040    public double getValue();
041    
042    /** Weighted value of the objectives */
043    public double getWeightedValue();
044    
045    /** Bounds (minimum and maximum) estimate for the value */
046    public double[] getBounds();
047    
048    /** Weighted best value of the objective (value in the best solution). */
049    public double getWeightedBest();
050
051    /** Best value (value of the criterion in the best solution) */
052    public double getBest();
053    
054    /** Weight of the criterion */
055    public double getWeight();
056    
057    /** Weighted value of a proposed assignment (including hard conflicts) */
058    public double getWeightedValue(T value, Set<T> conflicts);
059    
060    /** Value of a proposed assignment (including hard conflicts) */
061    public double getValue(T value, Set<T> conflicts);
062    
063    /** Weighted value of a part of the problem (given by the collection of variables) */
064    public double getWeightedValue(Collection<V> variables);
065    
066    /** Value of a part of the problem (given by the collection of variables) */
067    public double getValue(Collection<V> variables);
068    
069    /** Value bounds (minimum and maximum) of the criterion on a part of the problem */
070    public double[] getBounds(Collection<V> variables);
071    
072    /** Criterion name */
073    public String getName();
074    
075    /** Outside update of the criterion (usefull when the criterion is driven by a set of constraints). */
076    public void inc(double value);
077    
078    /** Notification that the current solution has been saved to the best. */
079    public void bestSaved();
080
081    /** Notification that the current solution has been restored from the best. */
082    public void bestRestored();
083}