    001package net.sf.cpsolver.coursett.criteria;
    002
    003import java.util.Collection;
    004import java.util.HashSet;
    005import java.util.Set;
    006
    007import net.sf.cpsolver.coursett.constraint.GroupConstraint;
    008import net.sf.cpsolver.coursett.model.Lecture;
    009import net.sf.cpsolver.coursett.model.Placement;
    010import net.sf.cpsolver.coursett.model.TimetableModel;
    011import net.sf.cpsolver.ifs.util.DataProperties;
    012
    013/**
    014 * Distribution preferences. This criterion counts how well the soft distribution preferences
    015 * are met. This is a sum of {@link GroupConstraint#getPreference()} of all soft distribution
    016 * (group) constraints.
    017 * <br>
    018 *
    019 * @version CourseTT 1.2 (University Course Timetabling)<br>
    020 *          Copyright (C) 2006 - 2011 Tomáš Müller<br>
    021 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    022 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    023 * <br>
    024 *          This library is free software; you can redistribute it and/or modify
    025 *          it under the terms of the GNU Lesser General Public License as
    026 *          published by the Free Software Foundation; either version 3 of the
    027 *          License, or (at your option) any later version. <br>
    028 * <br>
    029 *          This library is distributed in the hope that it will be useful, but
    030 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    031 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    032 *          Lesser General Public License for more details. <br>
    033 * <br>
    034 *          You should have received a copy of the GNU Lesser General Public
    035 *          License along with this library; if not see
    036 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
    037 */
    038public class DistributionPreferences extends TimetablingCriterion {
    039
    040    public DistributionPreferences() {
    041        iValueUpdateType = ValueUpdateType.NoUpdate;
    042    }
    043
    044    @Override
    045    public double getWeightDefault(DataProperties config) {
    046        return config.getPropertyDouble("Comparator.ContrPreferenceWeight", 1.0);
    047    }
    048
    049    @Override
    050    public String getPlacementSelectionWeightName() {
    051        return "Placement.ConstrPreferenceWeight";
    052    }
    053
    054
    055    @Override
    056    public double getValue(Placement value, Set<Placement> conflicts) {
    057        double ret = 0.0;
    058        for (GroupConstraint gc : value.variable().groupConstraints())
    059            ret += gc.getCurrentPreference(value);
    060        return ret;
    061    }
    062
    063    @Override
    064    public double getValue(Collection<Lecture> variables) {
    065        double ret = 0;
    066        Set<GroupConstraint> constraints = new HashSet<GroupConstraint>();
    067        for (Lecture lect: variables) {
    068            for (GroupConstraint gc: lect.groupConstraints()) {
    069                if (!constraints.add(gc)) continue;
    070                ret += gc.getCurrentPreference();
    071            }
    072        }
    073        return ret;
    074    }
    075
    076    @Override
    077    protected double[] computeBounds() {
    078        double[] bounds = new double[] { 0.0, 0.0 };
    079        for (GroupConstraint gc: ((TimetableModel)getModel()).getGroupConstraints()) {
    080            if (!gc.isHard()) {
    081                bounds[0] -= Math.abs(gc.getPreference());
    082                bounds[1] += Math.abs(gc.getPreference()) * (gc.variables().size() * (gc.variables().size() - 1)) / 2;
    083            }
    084        }
    085        return bounds;
    086    }
    087
    088    @Override
    089    public double[] getBounds(Collection<Lecture> variables) {
    090        double[] bounds = new double[] { 0.0, 0.0 };
    091        Set<GroupConstraint> constraints = new HashSet<GroupConstraint>();
    092        for (Lecture lect: variables) {
    093            for (GroupConstraint gc: lect.groupConstraints()) {
    094                if (!gc.isHard() && constraints.add(gc)) {
    095                    bounds[0] -= Math.abs(gc.getPreference());
    096                    bounds[1] += Math.abs(gc.getPreference()) * (gc.variables().size() * (gc.variables().size() - 1)) / 2;
    097                }
    098            }
    099        }
    100        return bounds;
    101    }
    102}