    001package org.cpsolver.coursett.criteria;
    002
    003import java.util.Collection;
    004import java.util.HashSet;
    005import java.util.Set;
    006
    007import org.cpsolver.coursett.constraint.GroupConstraint;
    008import org.cpsolver.coursett.model.Lecture;
    009import org.cpsolver.coursett.model.Placement;
    010import org.cpsolver.coursett.model.TimetableModel;
    011import org.cpsolver.ifs.assignment.Assignment;
    012import org.cpsolver.ifs.util.DataProperties;
    013
    014
    015/**
    016 * Distribution preferences. This criterion counts how well the soft distribution preferences
    017 * are met. This is a sum of {@link GroupConstraint#getPreference()} of all soft distribution
    018 * (group) constraints.
    019 * <br>
    020 *
    021 * @version CourseTT 1.3 (University Course Timetabling)<br>
    022 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
    023 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    024 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    025 * <br>
    026 *          This library is free software; you can redistribute it and/or modify
    027 *          it under the terms of the GNU Lesser General Public License as
    028 *          published by the Free Software Foundation; either version 3 of the
    029 *          License, or (at your option) any later version. <br>
    030 * <br>
    031 *          This library is distributed in the hope that it will be useful, but
    032 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    033 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    034 *          Lesser General Public License for more details. <br>
    035 * <br>
    036 *          You should have received a copy of the GNU Lesser General Public
    037 *          License along with this library; if not see
    038 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
    039 */
    040public class DistributionPreferences extends TimetablingCriterion {
    041
    042    public DistributionPreferences() {
    043        setValueUpdateType(ValueUpdateType.NoUpdate);
    044    }
    045
    046    @Override
    047    public double getWeightDefault(DataProperties config) {
    048        return config.getPropertyDouble("Comparator.ContrPreferenceWeight", 1.0);
    049    }
    050
    051    @Override
    052    public String getPlacementSelectionWeightName() {
    053        return "Placement.ConstrPreferenceWeight";
    054    }
    055
    056
    057    @Override
    058    public double getValue(Assignment<Lecture, Placement> assignment, Placement value, Set<Placement> conflicts) {
    059        double ret = 0.0;
    060        for (GroupConstraint gc : value.variable().groupConstraints())
    061            ret += gc.getCurrentPreference(assignment, value);
    062        return ret;
    063    }
    064
    065    @Override
    066    public double getValue(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) {
    067        double ret = 0;
    068        Set<GroupConstraint> constraints = new HashSet<GroupConstraint>();
    069        for (Lecture lect: variables) {
    070            for (GroupConstraint gc: lect.groupConstraints()) {
    071                if (!constraints.add(gc)) continue;
    072                ret += gc.getContext(assignment).getPreference();
    073            }
    074        }
    075        return ret;
    076    }
    077
    078    @Override
    079    protected double[] computeBounds(Assignment<Lecture, Placement> assignment) {
    080        double[] bounds = new double[] { 0.0, 0.0 };
    081        for (GroupConstraint gc: ((TimetableModel)getModel()).getGroupConstraints()) {
    082            if (!gc.isHard()) {
    083                bounds[1] += Math.abs(gc.getPreference()) * (1 + (gc.variables().size() * (gc.variables().size() - 1)) / 2);
    084            }
    085        }
    086        return bounds;
    087    }
    088
    089    @Override
    090    public double[] getBounds(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) {
    091        double[] bounds = new double[] { 0.0, 0.0 };
    092        Set<GroupConstraint> constraints = new HashSet<GroupConstraint>();
    093        for (Lecture lect: variables) {
    094            for (GroupConstraint gc: lect.groupConstraints()) {
    095                if (!gc.isHard() && constraints.add(gc)) {
    096                    bounds[1] += Math.abs(gc.getPreference()) * (1 + (gc.variables().size() * (gc.variables().size() - 1)) / 2);
    097                }
    098            }
    099        }
    100        return bounds;
    101    }
    102}