001    package net.sf.cpsolver.ifs.criteria;
002    
003    import java.util.Collection;
004    import java.util.Set;
005    
006    import net.sf.cpsolver.ifs.model.InfoProvider;
007    import net.sf.cpsolver.ifs.model.ModelListener;
008    import net.sf.cpsolver.ifs.model.Value;
009    import 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 Tomas Muller<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     */
037    public 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    }