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.Constants;
008import net.sf.cpsolver.coursett.constraint.JenrlConstraint;
009import net.sf.cpsolver.coursett.model.Lecture;
010import net.sf.cpsolver.coursett.model.Placement;
011import net.sf.cpsolver.coursett.model.Student;
012import net.sf.cpsolver.coursett.model.TimeLocation;
013import net.sf.cpsolver.coursett.model.TimetableModel;
014import net.sf.cpsolver.ifs.solver.Solver;
015import net.sf.cpsolver.ifs.util.DistanceMetric;
016
017/**
018 * Student conflicts. This criterion counts student conflicts between classes. A conflict
019 * occurs when two classes that are attended by the same student (or students) are overlapping
020 * in time or place back-to-back in rooms that are too far a part. The combinations of classes
021 * that share students are maintained by {@link JenrlConstraint}.  
022 * <br>
023 * 
024 * @version CourseTT 1.2 (University Course Timetabling)<br>
025 *          Copyright (C) 2006 - 2011 Tomáš Müller<br>
026 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
027 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
028 * <br>
029 *          This library is free software; you can redistribute it and/or modify
030 *          it under the terms of the GNU Lesser General Public License as
031 *          published by the Free Software Foundation; either version 3 of the
032 *          License, or (at your option) any later version. <br>
033 * <br>
034 *          This library is distributed in the hope that it will be useful, but
035 *          WITHOUT ANY WARRANTY; without even the implied warranty of
036 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
037 *          Lesser General Public License for more details. <br>
038 * <br>
039 *          You should have received a copy of the GNU Lesser General Public
040 *          License along with this library; if not see
041 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
042 */
043public class StudentConflict extends TimetablingCriterion {
044    protected boolean iIncludeConflicts = false;
045    
046    public StudentConflict() {
047        iValueUpdateType = ValueUpdateType.BeforeUnassignedBeforeAssigned;
048    }
049    
050    @Override
051    public boolean init(Solver<Lecture, Placement> solver) {
052        iIncludeConflicts = solver.getProperties().getPropertyBoolean("StudentConflict.IncludeConflicts", false);
053        return super.init(solver);
054    }
055    
056    @Override
057    public String getPlacementSelectionWeightName() {
058        return null;
059    }
060
061    @Override
062    public double getValue() {
063        return super.getValue();
064    }
065    
066    public DistanceMetric getMetrics() {
067        return (getModel() == null ? null : ((TimetableModel)getModel()).getDistanceMetric());
068    }
069
070    public static boolean overlaps(Placement p1, Placement p2) {
071        return p1 != null && p2 != null && p1.getTimeLocation().hasIntersection(p2.getTimeLocation()) && (!p1.variable().isCommitted() || !p2.variable().isCommitted());
072    }
073    
074    protected double jointEnrollment(JenrlConstraint jenrl) {
075        return jenrl.jenrl();
076    }
077    
078    public static boolean distance(DistanceMetric m, Placement p1, Placement p2) {
079        if (m == null && p1 != null) m = ((TimetableModel)p1.variable().getModel()).getDistanceMetric();
080        if (m == null && p2 != null) m = ((TimetableModel)p2.variable().getModel()).getDistanceMetric();
081        if (p1 == null || p2 == null || m == null) return false;
082        if (p1.variable().isCommitted() && p2.variable().isCommitted()) return false;
083        TimeLocation t1 = p1.getTimeLocation(), t2 = p2.getTimeLocation();
084        if (!t1.shareDays(t2) || !t1.shareWeeks(t2)) return false;
085        if (m.doComputeDistanceConflictsBetweenNonBTBClasses()) {
086            if (t1.getStartSlot() + t1.getLength() <= t2.getStartSlot()) {
087                return Placement.getDistanceInMinutes(m, p1, p2) > t1.getBreakTime() + Constants.SLOT_LENGTH_MIN * (t2.getStartSlot() - t1.getStartSlot() - t1.getLength());
088            } else if (t2.getStartSlot() + t2.getLength() <= t1.getStartSlot()) {
089                return Placement.getDistanceInMinutes(m, p1, p2) > t2.getBreakTime() + Constants.SLOT_LENGTH_MIN * (t1.getStartSlot() - t2.getStartSlot() - t2.getLength());
090            }
091        } else {
092            if (t1.getStartSlot() + t1.getLength() == t2.getStartSlot()) {
093                return Placement.getDistanceInMinutes(m, p1, p2) > t1.getBreakTime();
094            } else if (t2.getStartSlot() + t2.getLength() == t1.getStartSlot()) {
095                return Placement.getDistanceInMinutes(m, p1, p2) > t2.getBreakTime();
096            }
097        }
098        return false;
099    }
100    
101    public static boolean ignore(Placement p1, Placement p2) {
102        return p1 != null && p2 != null && p1.variable().isToIgnoreStudentConflictsWith(p2.variable());
103    }
104    
105    public static boolean ignore(Lecture l1, Lecture l2) {
106        return l1 != null && l2 != null && l1.isToIgnoreStudentConflictsWith(l2);
107    }
108    
109    public static boolean committed(Placement p1, Placement p2) {
110        return p1 != null && p2 != null && committed(p1.variable(), p2.variable());
111    }
112    
113    public static boolean committed(Lecture l1, Lecture l2) {
114        return l1 != null && l2 != null && (l1.isCommitted() || l2.isCommitted()) && (!l1.isCommitted() || !l2.isCommitted());
115    }
116    
117    public static boolean applicable(Placement p1, Placement p2) {
118        return p1 != null && p2 != null && applicable(p1.variable(), p2.variable());
119    }
120    
121    public static boolean applicable(Lecture l1, Lecture l2) {
122        return l1 != null && l2 != null && (!l1.isCommitted() || !l2.isCommitted());
123    }
124
125    public static boolean hard(Placement p1, Placement p2) {
126        return p1 != null && p2 != null && hard(p1.variable(), p2.variable());
127    }
128    
129    public static boolean hard(Lecture l1, Lecture l2) {
130        return l1 != null && l2 != null && l1.isSingleSection() && l2.isSingleSection() && (!l1.isCommitted() || !l2.isCommitted());
131    }
132    
133    public boolean isApplicable(Lecture l1, Lecture l2) {
134        return !ignore(l1, l2) && applicable(l1, l2) && !committed(l1, l2); // exclude committed and outside student conflicts
135    }
136
137    public boolean inConflict(Placement p1, Placement p2) {
138        return !ignore(p1, p2) && (overlaps(p1, p2) || distance(getMetrics(), p1, p2)) && isApplicable(p1.variable(), p2.variable());
139    }
140    
141    @Override
142    public double getValue(Placement value, Set<Placement> conflicts) {
143        double ret = 0.0;
144        for (JenrlConstraint jenrl: value.variable().jenrlConstraints()) {
145            Placement another = jenrl.another(value.variable()).getAssignment();
146            if (another == null) continue;
147            if (conflicts != null && conflicts.contains(another)) continue;
148            if (inConflict(value, another))
149                ret += jointEnrollment(jenrl);
150        }
151        if (iIncludeConflicts && conflicts != null)
152            for (Placement conflict: conflicts) {
153                for (JenrlConstraint jenrl: conflict.variable().jenrlConstraints()) {
154                    Placement another = jenrl.another(conflict.variable()).getAssignment();
155                    if (another == null || another.variable().equals(value.variable())) continue;
156                    if (conflicts != null && conflicts.contains(another)) continue;
157                    if (inConflict(conflict, another))
158                        ret -= jointEnrollment(jenrl);
159                }
160            }
161        return ret;
162    }
163    
164    @Override
165    public double getValue(Collection<Lecture> variables) {
166        double ret = 0.0;
167        Set<JenrlConstraint> constraints = new HashSet<JenrlConstraint>();
168        for (Lecture lect: variables) {
169            if (lect.getAssignment() == null) continue;
170            for (JenrlConstraint jenrl: lect.jenrlConstraints()) {
171                if (!constraints.add(jenrl)) continue;
172                if (!jenrl.another(lect).isCommitted() && !variables.contains(jenrl.another(lect))) continue;
173                if (inConflict(lect.getAssignment(), jenrl.another(lect).getAssignment()))
174                    ret += jointEnrollment(jenrl);
175            }
176        }
177        return ret;
178    }
179
180    @Override
181    public double[] getBounds() {
182        double[] bounds = { 0.0, 0.0 };
183        for (JenrlConstraint jenrl: ((TimetableModel)getModel()).getJenrlConstraints())
184            if (isApplicable(jenrl.first(), jenrl.second()))
185                bounds[0] += jointEnrollment(jenrl);
186        return bounds;
187    }
188    
189    @Override
190    public double[] getBounds(Collection<Lecture> variables) {
191        double[] bounds = { 0.0, 0.0 };
192        Set<JenrlConstraint> constraints = new HashSet<JenrlConstraint>();
193        for (Lecture lect: variables) {
194            if (lect.getAssignment() == null) continue;
195            for (JenrlConstraint jenrl: lect.jenrlConstraints()) {
196                if (isApplicable(jenrl.first(), jenrl.second()) && constraints.add(jenrl) && (jenrl.another(lect).isCommitted() || variables.contains(jenrl.another(lect))))
197                    bounds[0] += jointEnrollment(jenrl);
198            }
199        }
200        return bounds;
201    }
202    
203    public void incJenrl(JenrlConstraint jenrl, double studentWeight, Double conflictPriority, Student student) {
204        if (inConflict(jenrl.first().getAssignment(), jenrl.second().getAssignment()))
205            iValue += studentWeight;
206    }
207    
208    @Override
209    public void bestRestored() {
210        super.bestRestored();
211        iValue = getValue(getModel().variables());
212    }
213}