001package org.cpsolver.coursett.criteria;
002
003import java.util.Collection;
004import java.util.HashSet;
005import java.util.Set;
006
007import org.cpsolver.coursett.Constants;
008import org.cpsolver.coursett.constraint.JenrlConstraint;
009import org.cpsolver.coursett.model.Lecture;
010import org.cpsolver.coursett.model.Placement;
011import org.cpsolver.coursett.model.Student;
012import org.cpsolver.coursett.model.TimeLocation;
013import org.cpsolver.coursett.model.TimetableModel;
014import org.cpsolver.ifs.assignment.Assignment;
015import org.cpsolver.ifs.solver.Solver;
016import org.cpsolver.ifs.util.DistanceMetric;
017
018
019/**
020 * Student conflicts. This criterion counts student conflicts between classes. A conflict
021 * occurs when two classes that are attended by the same student (or students) are overlapping
022 * in time or place back-to-back in rooms that are too far a part. The combinations of classes
023 * that share students are maintained by {@link JenrlConstraint}.  
024 * <br>
025 * 
026 * @version CourseTT 1.3 (University Course Timetabling)<br>
027 *          Copyright (C) 2006 - 2014 Tomas Muller<br>
028 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
029 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
030 * <br>
031 *          This library is free software; you can redistribute it and/or modify
032 *          it under the terms of the GNU Lesser General Public License as
033 *          published by the Free Software Foundation; either version 3 of the
034 *          License, or (at your option) any later version. <br>
035 * <br>
036 *          This library is distributed in the hope that it will be useful, but
037 *          WITHOUT ANY WARRANTY; without even the implied warranty of
038 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
039 *          Lesser General Public License for more details. <br>
040 * <br>
041 *          You should have received a copy of the GNU Lesser General Public
042 *          License along with this library; if not see
043 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
044 */
045public class StudentConflict extends TimetablingCriterion {
046    protected boolean iIncludeConflicts = false;
047    
048    public StudentConflict() {
049        setValueUpdateType(ValueUpdateType.BeforeUnassignedBeforeAssigned);
050    }
051    
052    @Override
053    public boolean init(Solver<Lecture, Placement> solver) {
054        iIncludeConflicts = solver.getProperties().getPropertyBoolean("StudentConflict.IncludeConflicts", false);
055        return super.init(solver);
056    }
057    
058    @Override
059    public String getPlacementSelectionWeightName() {
060        return null;
061    }
062
063    public DistanceMetric getMetrics() {
064        return (getModel() == null ? null : ((TimetableModel)getModel()).getDistanceMetric());
065    }
066
067    public static boolean overlaps(Placement p1, Placement p2) {
068        return p1 != null && p2 != null && p1.getTimeLocation().hasIntersection(p2.getTimeLocation()) && (!p1.variable().isCommitted() || !p2.variable().isCommitted());
069    }
070    
071    protected double jointEnrollment(JenrlConstraint jenrl) {
072        return jenrl.jenrl();
073    }
074    
075    public static boolean distance(DistanceMetric m, Placement p1, Placement p2) {
076        if (m == null && p1 != null) m = ((TimetableModel)p1.variable().getModel()).getDistanceMetric();
077        if (m == null && p2 != null) m = ((TimetableModel)p2.variable().getModel()).getDistanceMetric();
078        if (p1 == null || p2 == null || m == null) return false;
079        if (p1.variable().isCommitted() && p2.variable().isCommitted()) return false;
080        TimeLocation t1 = p1.getTimeLocation(), t2 = p2.getTimeLocation();
081        if (!t1.shareDays(t2) || !t1.shareWeeks(t2)) return false;
082        if (m.doComputeDistanceConflictsBetweenNonBTBClasses()) {
083            if (t1.getStartSlot() + t1.getLength() <= t2.getStartSlot()) {
084                return Placement.getDistanceInMinutes(m, p1, p2) > t1.getBreakTime() + Constants.SLOT_LENGTH_MIN * (t2.getStartSlot() - t1.getStartSlot() - t1.getLength());
085            } else if (t2.getStartSlot() + t2.getLength() <= t1.getStartSlot()) {
086                return Placement.getDistanceInMinutes(m, p1, p2) > t2.getBreakTime() + Constants.SLOT_LENGTH_MIN * (t1.getStartSlot() - t2.getStartSlot() - t2.getLength());
087            }
088        } else {
089            if (t1.getStartSlot() + t1.getLength() == t2.getStartSlot()) {
090                return Placement.getDistanceInMinutes(m, p1, p2) > t1.getBreakTime();
091            } else if (t2.getStartSlot() + t2.getLength() == t1.getStartSlot()) {
092                return Placement.getDistanceInMinutes(m, p1, p2) > t2.getBreakTime();
093            }
094        }
095        return false;
096    }
097    
098    public static boolean ignore(Lecture l1, Lecture l2) {
099        return l1 != null && l2 != null && l1.isToIgnoreStudentConflictsWith(l2);
100    }
101    
102    public static boolean committed(Lecture l1, Lecture l2) {
103        return l1 != null && l2 != null && (l1.isCommitted() || l2.isCommitted()) && (!l1.isCommitted() || !l2.isCommitted());
104    }
105    
106    public static boolean uncommitted(Lecture l1, Lecture l2) {
107        return l1 != null && l2 != null && !l1.isCommitted() && !l2.isCommitted();
108    }
109    
110    public static boolean applicable(Lecture l1, Lecture l2) {
111        return l1 != null && l2 != null && (!l1.isCommitted() || !l2.isCommitted());
112    }
113
114    public static boolean hard(Lecture l1, Lecture l2) {
115        return l1 != null && l2 != null && l1.isSingleSection() && l2.isSingleSection() && (!l1.isCommitted() || !l2.isCommitted());
116    }
117    
118    public boolean isApplicable(Lecture l1, Lecture l2) {
119        return l1 != null && l2 != null && !ignore(l1, l2) && uncommitted(l1, l2); // exclude committed and outside student conflicts
120    }
121    public boolean inConflict(Placement p1, Placement p2) {
122        return overlaps(p1, p2) || distance(getMetrics(), p1, p2);
123    }
124    
125    @Override
126    public double getValue(Assignment<Lecture, Placement> assignment, Placement value, Set<Placement> conflicts) {
127        double ret = 0.0;
128        for (JenrlConstraint jenrl: value.variable().jenrlConstraints()) {
129            Lecture other = jenrl.another(value.variable());
130            if (!isApplicable(value.variable(), other)) continue;
131            Placement another = assignment.getValue(other);
132            if (another == null) continue;
133            if (conflicts != null && conflicts.contains(another)) continue;
134            if (inConflict(value, another))
135                ret += jointEnrollment(jenrl);
136        }
137        if (iIncludeConflicts && conflicts != null)
138            for (Placement conflict: conflicts) {
139                for (JenrlConstraint jenrl: conflict.variable().jenrlConstraints()) {
140                    Lecture other = jenrl.another(conflict.variable());
141                    if (!isApplicable(conflict.variable(), other)) continue;
142                    Placement another = assignment.getValue(other);
143                    if (another == null || another.variable().equals(value.variable())) continue;
144                    if (conflicts != null && conflicts.contains(another)) continue;
145                    if (inConflict(conflict, another))
146                        ret -= jointEnrollment(jenrl);
147                }
148            }
149        return ret;
150    }
151    
152    @Override
153    public double getValue(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) {
154        double ret = 0.0;
155        Set<JenrlConstraint> constraints = new HashSet<JenrlConstraint>();
156        for (Lecture lect: variables) {
157            Placement plac = assignment.getValue(lect);
158            if (plac == null) continue;
159            for (JenrlConstraint jenrl: lect.jenrlConstraints()) {
160                if (!constraints.add(jenrl)) continue;
161                Lecture other = jenrl.another(lect);
162                if (!other.isCommitted() && !variables.contains(other)) continue;
163                if (!isApplicable(lect, other)) continue;
164                if (inConflict(plac, assignment.getValue(other)))
165                    ret += jointEnrollment(jenrl);
166            }
167        }
168        return ret;
169    }
170
171    @Override
172    public double[] getBounds(Assignment<Lecture, Placement> assignment) {
173        double[] bounds = { 0.0, 0.0 };
174        for (JenrlConstraint jenrl: ((TimetableModel)getModel()).getJenrlConstraints())
175            if (isApplicable(jenrl.first(), jenrl.second()))
176                bounds[0] += jointEnrollment(jenrl);
177        return bounds;
178    }
179    
180    @Override
181    public double[] getBounds(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) {
182        double[] bounds = { 0.0, 0.0 };
183        Set<JenrlConstraint> constraints = new HashSet<JenrlConstraint>();
184        for (Lecture lect: variables) {
185            if (assignment.getValue(lect) == null) continue;
186            for (JenrlConstraint jenrl: lect.jenrlConstraints()) {
187                if (isApplicable(jenrl.first(), jenrl.second()) && constraints.add(jenrl) && (jenrl.another(lect).isCommitted() || variables.contains(jenrl.another(lect))))
188                    bounds[0] += jointEnrollment(jenrl);
189            }
190        }
191        return bounds;
192    }
193    
194    public void incJenrl(Assignment<Lecture, Placement> assignment, JenrlConstraint jenrl, double studentWeight, Double conflictPriority, Student student) {
195        if (isApplicable(jenrl.first(), jenrl.second()) && inConflict(assignment.getValue(jenrl.first()), assignment.getValue(jenrl.second())))
196            super.inc(assignment, studentWeight);
197    }
198    
199    @Override
200    public void bestRestored(Assignment<Lecture, Placement> assignment) {
201        super.bestRestored(assignment);
202        getContext(assignment).setTotal(getValue(assignment, getModel().variables()));
203    }
204}