001package org.cpsolver.coursett.model;
002
003import java.util.ArrayList;
004import java.util.BitSet;
005import java.util.Collection;
006import java.util.HashSet;
007import java.util.HashMap;
008import java.util.List;
009import java.util.Locale;
010import java.util.Map;
011import java.util.Set;
012
013import org.cpsolver.coursett.Constants;
014import org.cpsolver.coursett.constraint.ClassLimitConstraint;
015import org.cpsolver.coursett.constraint.DepartmentSpreadConstraint;
016import org.cpsolver.coursett.constraint.FlexibleConstraint;
017import org.cpsolver.coursett.constraint.GroupConstraint;
018import org.cpsolver.coursett.constraint.InstructorConstraint;
019import org.cpsolver.coursett.constraint.JenrlConstraint;
020import org.cpsolver.coursett.constraint.RoomConstraint;
021import org.cpsolver.coursett.constraint.SpreadConstraint;
022import org.cpsolver.coursett.criteria.BackToBackInstructorPreferences;
023import org.cpsolver.coursett.criteria.BrokenTimePatterns;
024import org.cpsolver.coursett.criteria.DepartmentBalancingPenalty;
025import org.cpsolver.coursett.criteria.DistributionPreferences;
026import org.cpsolver.coursett.criteria.FlexibleConstraintCriterion;
027import org.cpsolver.coursett.criteria.Perturbations;
028import org.cpsolver.coursett.criteria.RoomPreferences;
029import org.cpsolver.coursett.criteria.RoomViolations;
030import org.cpsolver.coursett.criteria.SameSubpartBalancingPenalty;
031import org.cpsolver.coursett.criteria.StudentCommittedConflict;
032import org.cpsolver.coursett.criteria.StudentConflict;
033import org.cpsolver.coursett.criteria.StudentDistanceConflict;
034import org.cpsolver.coursett.criteria.StudentHardConflict;
035import org.cpsolver.coursett.criteria.StudentOverlapConflict;
036import org.cpsolver.coursett.criteria.StudentWorkdayConflict;
037import org.cpsolver.coursett.criteria.TimePreferences;
038import org.cpsolver.coursett.criteria.TimeViolations;
039import org.cpsolver.coursett.criteria.TooBigRooms;
040import org.cpsolver.coursett.criteria.UselessHalfHours;
041import org.cpsolver.coursett.criteria.additional.InstructorConflict;
042import org.cpsolver.coursett.criteria.placement.DeltaTimePreference;
043import org.cpsolver.coursett.criteria.placement.HardConflicts;
044import org.cpsolver.coursett.criteria.placement.PotentialHardConflicts;
045import org.cpsolver.coursett.criteria.placement.WeightedHardConflicts;
046import org.cpsolver.ifs.assignment.Assignment;
047import org.cpsolver.ifs.constant.ConstantModel;
048import org.cpsolver.ifs.criteria.Criterion;
049import org.cpsolver.ifs.model.Constraint;
050import org.cpsolver.ifs.model.GlobalConstraint;
051import org.cpsolver.ifs.model.InfoProvider;
052import org.cpsolver.ifs.model.WeakeningConstraint;
053import org.cpsolver.ifs.solution.Solution;
054import org.cpsolver.ifs.termination.TerminationCondition;
055import org.cpsolver.ifs.util.DataProperties;
056import org.cpsolver.ifs.util.DistanceMetric;
057
058
059/**
060 * Timetable model.
061 * 
062 * @version CourseTT 1.3 (University Course Timetabling)<br>
063 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
064 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
065 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
066 * <br>
067 *          This library is free software; you can redistribute it and/or modify
068 *          it under the terms of the GNU Lesser General Public License as
069 *          published by the Free Software Foundation; either version 3 of the
070 *          License, or (at your option) any later version. <br>
071 * <br>
072 *          This library is distributed in the hope that it will be useful, but
073 *          WITHOUT ANY WARRANTY; without even the implied warranty of
074 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
075 *          Lesser General Public License for more details. <br>
076 * <br>
077 *          You should have received a copy of the GNU Lesser General Public
078 *          License along with this library; if not see
079 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
080 */
081
082public class TimetableModel extends ConstantModel<Lecture, Placement> {
083    private static org.apache.log4j.Logger sLogger = org.apache.log4j.Logger.getLogger(TimetableModel.class);
084    private static java.text.DecimalFormat sDoubleFormat = new java.text.DecimalFormat("0.00",
085            new java.text.DecimalFormatSymbols(Locale.US));
086
087    private List<InstructorConstraint> iInstructorConstraints = new ArrayList<InstructorConstraint>();
088    private List<JenrlConstraint> iJenrlConstraints = new ArrayList<JenrlConstraint>();
089    private List<RoomConstraint> iRoomConstraints = new ArrayList<RoomConstraint>();
090    private List<DepartmentSpreadConstraint> iDepartmentSpreadConstraints = new ArrayList<DepartmentSpreadConstraint>();
091    private List<SpreadConstraint> iSpreadConstraints = new ArrayList<SpreadConstraint>();
092    private List<GroupConstraint> iGroupConstraints = new ArrayList<GroupConstraint>();
093    private List<ClassLimitConstraint> iClassLimitConstraints = new ArrayList<ClassLimitConstraint>();
094    private List<FlexibleConstraint> iFlexibleConstraints = new ArrayList<FlexibleConstraint>();
095    private DataProperties iProperties = null;
096    private int iYear = -1;
097    private List<BitSet> iWeeks = null;
098    private boolean iOnFlySectioning = false;
099    private int iStudentWorkDayLimit = -1;
100    private boolean iAllowBreakHard = false;
101
102    private HashSet<Student> iAllStudents = new HashSet<Student>();
103    
104    private DistanceMetric iDistanceMetric = null;
105    
106    private StudentSectioning iStudentSectioning = null;
107    private List<StudentGroup> iStudentGroups = new ArrayList<StudentGroup>();
108
109    @SuppressWarnings("unchecked")
110    public TimetableModel(DataProperties properties) {
111        super();
112        iProperties = properties;
113        iDistanceMetric = new DistanceMetric(properties);
114        if (properties.getPropertyBoolean("OnFlySectioning.Enabled", false)) {
115            addModelListener(new OnFlySectioning(this)); iOnFlySectioning = true;
116        }
117        iStudentWorkDayLimit = properties.getPropertyInt("StudentConflict.WorkDayLimit", -1);
118        iAllowBreakHard = properties.getPropertyBoolean("General.AllowBreakHard", false);
119        String criteria = properties.getProperty("General.Criteria",
120                // Objectives
121                StudentConflict.class.getName() + ";" +
122                StudentDistanceConflict.class.getName() + ";" +
123                StudentHardConflict.class.getName() + ";" +
124                StudentCommittedConflict.class.getName() + ";" +
125                StudentOverlapConflict.class.getName() + ";" +
126                UselessHalfHours.class.getName() + ";" +
127                BrokenTimePatterns.class.getName() + ";" +
128                TooBigRooms.class.getName() + ";" +
129                TimePreferences.class.getName() + ";" +
130                RoomPreferences.class.getName() + ";" +
131                DistributionPreferences.class.getName() + ";" +
132                SameSubpartBalancingPenalty.class.getName() + ";" +
133                DepartmentBalancingPenalty.class.getName() + ";" +
134                BackToBackInstructorPreferences.class.getName() + ";" +
135                Perturbations.class.getName() + ";" +
136                // Additional placement selection criteria
137                // AssignmentCount.class.getName() + ";" +
138                DeltaTimePreference.class.getName() + ";" +
139                HardConflicts.class.getName() + ";" +
140                PotentialHardConflicts.class.getName() + ";" +
141                FlexibleConstraintCriterion.class.getName() + ";" +
142                WeightedHardConflicts.class.getName());
143        if (iStudentWorkDayLimit > 0)
144            criteria += ";" + StudentWorkdayConflict.class.getName();
145        // Interactive mode -- count time / room violations
146        if (properties.getPropertyBoolean("General.InteractiveMode", false))
147            criteria += ";" + TimeViolations.class.getName() + ";" + RoomViolations.class.getName();
148        else if (properties.getPropertyBoolean("General.AllowProhibitedRooms", false)) {
149            criteria += ";" + RoomViolations.class.getName();
150            iAllowBreakHard = true;
151        }
152        // Additional (custom) criteria
153        criteria += ";" + properties.getProperty("General.AdditionalCriteria", "");
154        for (String criterion: criteria.split("\\;")) {
155            if (criterion == null || criterion.isEmpty()) continue;
156            try {
157                Class<Criterion<Lecture, Placement>> clazz = (Class<Criterion<Lecture, Placement>>)Class.forName(criterion);
158                Criterion<Lecture, Placement> c = clazz.newInstance();
159                c.configure(properties);
160                addCriterion(c);
161            } catch (Exception e) {
162                sLogger.error("Unable to use " + criterion + ": " + e.getMessage());
163            }
164        }
165        if (properties.getPropertyBoolean("General.SoftInstructorConstraints", false)) {
166            InstructorConflict ic = new InstructorConflict(); ic.configure(properties);
167            addCriterion(ic);
168        }
169        try {
170            String studentSectioningClassName = properties.getProperty("StudentSectioning.Class", DefaultStudentSectioning.class.getName());
171            Class<?> studentSectioningClass = Class.forName(studentSectioningClassName);
172            iStudentSectioning = (StudentSectioning)studentSectioningClass.getConstructor(TimetableModel.class).newInstance(this);
173        } catch (Exception e) {
174            sLogger.error("Failed to load custom student sectioning class: " + e.getMessage());
175            iStudentSectioning = new DefaultStudentSectioning(this);
176        }
177        if (iStudentSectioning instanceof InfoProvider<?, ?>) {
178            getInfoProviders().add((InfoProvider<Lecture, Placement>)iStudentSectioning);
179        }
180    }
181
182    public DistanceMetric getDistanceMetric() {
183        return iDistanceMetric;
184    }
185    
186    public int getStudentWorkDayLimit() {
187        return iStudentWorkDayLimit;
188    }
189    
190    /**
191     * Returns interface to the student sectioning functions needed during course timetabling.
192     * Defaults to an instance of {@link DefaultStudentSectioning}, can be changed using the StudentSectioning.Class parameter.
193     * @return student sectioning
194     */
195    public StudentSectioning getStudentSectioning() {
196        return iStudentSectioning;
197    }
198
199    public DataProperties getProperties() {
200        return iProperties;
201    }
202
203    /**
204     * Student final sectioning (switching students between sections of the same
205     * class in order to minimize overall number of student conflicts)
206     * @param assignment current assignment
207     * @param termination optional termination condition
208     */
209    public void switchStudents(Assignment<Lecture, Placement> assignment, TerminationCondition<Lecture, Placement> termination) {
210        getStudentSectioning().switchStudents(new Solution<Lecture, Placement>(this, assignment), termination);
211    }
212    
213    /**
214     * Student final sectioning (switching students between sections of the same
215     * class in order to minimize overall number of student conflicts)
216     * @param assignment current assignment
217     */
218    public void switchStudents(Assignment<Lecture, Placement> assignment) {
219        getStudentSectioning().switchStudents(new Solution<Lecture, Placement>(this, assignment), null);
220    }
221
222    public Map<String, String> getBounds(Assignment<Lecture, Placement> assignment) {
223        Map<String, String> ret = new HashMap<String, String>();
224        ret.put("Room preferences min", "" + getCriterion(RoomPreferences.class).getBounds(assignment)[0]);
225        ret.put("Room preferences max", "" + getCriterion(RoomPreferences.class).getBounds(assignment)[1]);
226        ret.put("Time preferences min", "" + getCriterion(TimePreferences.class).getBounds(assignment)[0]);
227        ret.put("Time preferences max", "" + getCriterion(TimePreferences.class).getBounds(assignment)[1]);
228        ret.put("Distribution preferences min", "" + getCriterion(DistributionPreferences.class).getBounds(assignment)[0]);
229        ret.put("Distribution preferences max", "" + getCriterion(DistributionPreferences.class).getBounds(assignment)[1]);
230        if (getProperties().getPropertyBoolean("General.UseDistanceConstraints", false)) {
231            ret.put("Back-to-back instructor preferences max", "" + getCriterion(BackToBackInstructorPreferences.class).getBounds(assignment)[1]);
232        }
233        ret.put("Too big rooms max", "" + getCriterion(TooBigRooms.class).getBounds(assignment)[0]);
234        ret.put("Useless half-hours", "" + getCriterion(UselessHalfHours.class).getBounds(assignment)[0]);
235        return ret;
236    }
237
238    /** Global info */
239    @Override
240    public Map<String, String> getInfo(Assignment<Lecture, Placement> assignment) {
241        Map<String, String> ret = super.getInfo(assignment);
242        ret.put("Memory usage", getMem());
243        
244        Criterion<Lecture, Placement> rp = getCriterion(RoomPreferences.class);
245        Criterion<Lecture, Placement> rv = getCriterion(RoomViolations.class);
246        ret.put("Room preferences", getPerc(rp.getValue(assignment), rp.getBounds(assignment)[0], rp.getBounds(assignment)[1]) + "% (" + Math.round(rp.getValue(assignment)) + ")"
247                + (rv != null && rv.getValue(assignment) >= 0.5 ? " [hard:" + Math.round(rv.getValue(assignment)) + "]" : ""));
248        
249        Criterion<Lecture, Placement> tp = getCriterion(TimePreferences.class);
250        Criterion<Lecture, Placement> tv = getCriterion(TimeViolations.class);
251        ret.put("Time preferences", getPerc(tp.getValue(assignment), tp.getBounds(assignment)[0], tp.getBounds(assignment)[1]) + "% (" + sDoubleFormat.format(tp.getValue(assignment)) + ")"
252                + (tv != null && tv.getValue(assignment) >= 0.5 ? " [hard:" + Math.round(tv.getValue(assignment)) + "]" : ""));
253
254        Criterion<Lecture, Placement> dp = getCriterion(DistributionPreferences.class);
255        ret.put("Distribution preferences", getPerc(dp.getValue(assignment), dp.getBounds(assignment)[0], dp.getBounds(assignment)[1]) + "% (" + sDoubleFormat.format(dp.getValue(assignment)) + ")");
256        
257        Criterion<Lecture, Placement> sc = getCriterion(StudentConflict.class);
258        Criterion<Lecture, Placement> shc = getCriterion(StudentHardConflict.class);
259        Criterion<Lecture, Placement> sdc = getCriterion(StudentDistanceConflict.class);
260        Criterion<Lecture, Placement> scc = getCriterion(StudentCommittedConflict.class);
261        ret.put("Student conflicts", Math.round(scc.getValue(assignment) + sc.getValue(assignment)) +
262                " [committed:" + Math.round(scc.getValue(assignment)) +
263                ", distance:" + Math.round(sdc.getValue(assignment)) +
264                ", hard:" + Math.round(shc.getValue(assignment)) + "]");
265        
266        if (!getSpreadConstraints().isEmpty()) {
267            Criterion<Lecture, Placement> ip = getCriterion(BackToBackInstructorPreferences.class);
268            ret.put("Back-to-back instructor preferences", getPerc(ip.getValue(assignment), ip.getBounds(assignment)[0], ip.getBounds(assignment)[1]) + "% (" + Math.round(ip.getValue(assignment)) + ")");
269        }
270
271        if (!getDepartmentSpreadConstraints().isEmpty()) {
272            Criterion<Lecture, Placement> dbp = getCriterion(DepartmentBalancingPenalty.class);
273            ret.put("Department balancing penalty", sDoubleFormat.format(dbp.getValue(assignment)));
274        }
275        
276        Criterion<Lecture, Placement> sbp = getCriterion(SameSubpartBalancingPenalty.class);
277        ret.put("Same subpart balancing penalty", sDoubleFormat.format(sbp.getValue(assignment)));
278        
279        Criterion<Lecture, Placement> tbr = getCriterion(TooBigRooms.class);
280        ret.put("Too big rooms", getPercRev(tbr.getValue(assignment), tbr.getBounds(assignment)[1], tbr.getBounds(assignment)[0]) + "% (" + Math.round(tbr.getValue(assignment)) + ")");
281        
282        Criterion<Lecture, Placement> uh = getCriterion(UselessHalfHours.class);
283        Criterion<Lecture, Placement> bt = getCriterion(BrokenTimePatterns.class);
284
285        ret.put("Useless half-hours", getPercRev(uh.getValue(assignment) + bt.getValue(assignment), 0, Constants.sPreferenceLevelStronglyDiscouraged * bt.getBounds(assignment)[0]) +
286                "% (" + Math.round(uh.getValue(assignment)) + " + " + Math.round(bt.getValue(assignment)) + ")");
287        return ret;
288    }
289
290    @Override
291    public Map<String, String> getInfo(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) {
292        Map<String, String> ret = super.getInfo(assignment, variables);
293        
294        ret.put("Memory usage", getMem());
295        
296        Criterion<Lecture, Placement> rp = getCriterion(RoomPreferences.class);
297        ret.put("Room preferences", getPerc(rp.getValue(assignment, variables), rp.getBounds(assignment, variables)[0], rp.getBounds(assignment, variables)[1]) + "% (" + Math.round(rp.getValue(assignment, variables)) + ")");
298        
299        Criterion<Lecture, Placement> tp = getCriterion(TimePreferences.class);
300        ret.put("Time preferences", getPerc(tp.getValue(assignment, variables), tp.getBounds(assignment, variables)[0], tp.getBounds(assignment, variables)[1]) + "% (" + sDoubleFormat.format(tp.getValue(assignment, variables)) + ")"); 
301
302        Criterion<Lecture, Placement> dp = getCriterion(DistributionPreferences.class);
303        ret.put("Distribution preferences", getPerc(dp.getValue(assignment, variables), dp.getBounds(assignment, variables)[0], dp.getBounds(assignment, variables)[1]) + "% (" + sDoubleFormat.format(dp.getValue(assignment, variables)) + ")");
304        
305        Criterion<Lecture, Placement> sc = getCriterion(StudentConflict.class);
306        Criterion<Lecture, Placement> shc = getCriterion(StudentHardConflict.class);
307        Criterion<Lecture, Placement> sdc = getCriterion(StudentDistanceConflict.class);
308        Criterion<Lecture, Placement> scc = getCriterion(StudentCommittedConflict.class);
309        ret.put("Student conflicts", Math.round(scc.getValue(assignment, variables) + sc.getValue(assignment, variables)) +
310                " [committed:" + Math.round(scc.getValue(assignment, variables)) +
311                ", distance:" + Math.round(sdc.getValue(assignment, variables)) +
312                ", hard:" + Math.round(shc.getValue(assignment, variables)) + "]");
313        
314        if (!getSpreadConstraints().isEmpty()) {
315            Criterion<Lecture, Placement> ip = getCriterion(BackToBackInstructorPreferences.class);
316            ret.put("Back-to-back instructor preferences", getPerc(ip.getValue(assignment, variables), ip.getBounds(assignment, variables)[0], ip.getBounds(assignment, variables)[1]) + "% (" + Math.round(ip.getValue(assignment, variables)) + ")");
317        }
318
319        if (!getDepartmentSpreadConstraints().isEmpty()) {
320            Criterion<Lecture, Placement> dbp = getCriterion(DepartmentBalancingPenalty.class);
321            ret.put("Department balancing penalty", sDoubleFormat.format(dbp.getValue(assignment, variables)));
322        }
323        
324        Criterion<Lecture, Placement> sbp = getCriterion(SameSubpartBalancingPenalty.class);
325        ret.put("Same subpart balancing penalty", sDoubleFormat.format(sbp.getValue(assignment, variables)));
326        
327        Criterion<Lecture, Placement> tbr = getCriterion(TooBigRooms.class);
328        ret.put("Too big rooms", getPercRev(tbr.getValue(assignment, variables), tbr.getBounds(assignment, variables)[1], tbr.getBounds(assignment, variables)[0]) + "% (" + Math.round(tbr.getValue(assignment, variables)) + ")");
329        
330        Criterion<Lecture, Placement> uh = getCriterion(UselessHalfHours.class);
331        Criterion<Lecture, Placement> bt = getCriterion(BrokenTimePatterns.class);
332
333        ret.put("Useless half-hours", getPercRev(uh.getValue(assignment, variables) + bt.getValue(assignment, variables), 0, Constants.sPreferenceLevelStronglyDiscouraged * bt.getBounds(assignment, variables)[0]) +
334                "% (" + Math.round(uh.getValue(assignment, variables)) + " + " + Math.round(bt.getValue(assignment, variables)) + ")");
335        return ret;
336    }
337
338    @Override
339    public void addConstraint(Constraint<Lecture, Placement> constraint) {
340        super.addConstraint(constraint);
341        if (constraint instanceof InstructorConstraint) {
342            iInstructorConstraints.add((InstructorConstraint) constraint);
343        } else if (constraint instanceof JenrlConstraint) {
344            iJenrlConstraints.add((JenrlConstraint) constraint);
345        } else if (constraint instanceof RoomConstraint) {
346            iRoomConstraints.add((RoomConstraint) constraint);
347        } else if (constraint instanceof DepartmentSpreadConstraint) {
348            iDepartmentSpreadConstraints.add((DepartmentSpreadConstraint) constraint);
349        } else if (constraint instanceof SpreadConstraint) {
350            iSpreadConstraints.add((SpreadConstraint) constraint);
351        } else if (constraint instanceof ClassLimitConstraint) {
352            iClassLimitConstraints.add((ClassLimitConstraint) constraint);
353        } else if (constraint instanceof GroupConstraint) {
354            iGroupConstraints.add((GroupConstraint) constraint);
355        } else if (constraint instanceof FlexibleConstraint) {
356            iFlexibleConstraints.add((FlexibleConstraint) constraint);
357        }
358    }
359
360    @Override
361    public void removeConstraint(Constraint<Lecture, Placement> constraint) {
362        super.removeConstraint(constraint);
363        if (constraint instanceof InstructorConstraint) {
364            iInstructorConstraints.remove(constraint);
365        } else if (constraint instanceof JenrlConstraint) {
366            iJenrlConstraints.remove(constraint);
367        } else if (constraint instanceof RoomConstraint) {
368            iRoomConstraints.remove(constraint);
369        } else if (constraint instanceof DepartmentSpreadConstraint) {
370            iDepartmentSpreadConstraints.remove(constraint);
371        } else if (constraint instanceof SpreadConstraint) {
372            iSpreadConstraints.remove(constraint);
373        } else if (constraint instanceof ClassLimitConstraint) {
374            iClassLimitConstraints.remove(constraint);
375        } else if (constraint instanceof GroupConstraint) {
376            iGroupConstraints.remove(constraint);
377        } else if (constraint instanceof FlexibleConstraint) {
378            iFlexibleConstraints.remove(constraint);
379        }
380    }
381
382    /** The list of all instructor constraints 
383     * @return list of instructor constraints
384     **/
385    public List<InstructorConstraint> getInstructorConstraints() {
386        return iInstructorConstraints;
387    }
388
389    /** The list of all group constraints
390     * @return list of group (distribution) constraints
391     **/
392    public List<GroupConstraint> getGroupConstraints() {
393        return iGroupConstraints;
394    }
395
396    /** The list of all jenrl constraints
397     * @return list of join enrollment constraints
398     **/
399    public List<JenrlConstraint> getJenrlConstraints() {
400        return iJenrlConstraints;
401    }
402
403    /** The list of all room constraints 
404     * @return list of room constraints
405     **/
406    public List<RoomConstraint> getRoomConstraints() {
407        return iRoomConstraints;
408    }
409
410    /** The list of all departmental spread constraints 
411     * @return list of department spread constraints
412     **/
413    public List<DepartmentSpreadConstraint> getDepartmentSpreadConstraints() {
414        return iDepartmentSpreadConstraints;
415    }
416
417    public List<SpreadConstraint> getSpreadConstraints() {
418        return iSpreadConstraints;
419    }
420
421    public List<ClassLimitConstraint> getClassLimitConstraints() {
422        return iClassLimitConstraints;
423    }
424    
425    public List<FlexibleConstraint> getFlexibleConstraints() {
426        return iFlexibleConstraints;
427    }
428    
429    @Override
430    public double getTotalValue(Assignment<Lecture, Placement> assignment) {
431        double ret = 0;
432        for (Criterion<Lecture, Placement> criterion: getCriteria())
433            ret += criterion.getWeightedValue(assignment);
434        return ret;
435    }
436
437    @Override
438    public double getTotalValue(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) {
439        double ret = 0;
440        for (Criterion<Lecture, Placement> criterion: getCriteria())
441            ret += criterion.getWeightedValue(assignment, variables);
442        return ret;
443    }
444
445    public int getYear() {
446        return iYear;
447    }
448
449    public void setYear(int year) {
450        iYear = year;
451    }
452
453    public Set<Student> getAllStudents() {
454        return iAllStudents;
455    }
456
457    public void addStudent(Student student) {
458        iAllStudents.add(student);
459    }
460
461    public void removeStudent(Student student) {
462        iAllStudents.remove(student);
463    }
464
465    /**
466     * Returns amount of allocated memory.
467     * 
468     * @return amount of allocated memory to be written in the log
469     */
470    public static synchronized String getMem() {
471        Runtime rt = Runtime.getRuntime();
472        return sDoubleFormat.format(((double) (rt.totalMemory() - rt.freeMemory())) / 1048576) + "M";
473    }
474    
475    
476    /**
477     * Returns the set of conflicting variables with this value, if it is
478     * assigned to its variable. Conflicts with constraints that implement
479     * {@link WeakeningConstraint} are ignored.
480     * @param assignment current assignment
481     * @param value placement that is being considered
482     * @return computed conflicting assignments
483     */
484    public Set<Placement> conflictValuesSkipWeakeningConstraints(Assignment<Lecture, Placement> assignment, Placement value) {
485        Set<Placement> conflictValues = new HashSet<Placement>();
486        for (Constraint<Lecture, Placement> constraint : value.variable().hardConstraints()) {
487            if (constraint instanceof WeakeningConstraint) continue;
488            if (constraint instanceof GroupConstraint)
489                ((GroupConstraint)constraint).computeConflictsNoForwardCheck(assignment, value, conflictValues);
490            else
491                constraint.computeConflicts(assignment, value, conflictValues);
492        }
493        for (GlobalConstraint<Lecture, Placement> constraint : globalConstraints()) {
494            if (constraint instanceof WeakeningConstraint) continue;
495            constraint.computeConflicts(assignment, value, conflictValues);
496        }
497        return conflictValues;
498    }
499    
500    /**
501     * The method creates date patterns (bitsets) which represent the weeks of a
502     * semester.
503     *      
504     * @return a list of BitSets which represents the weeks of a semester.
505     */
506    public List<BitSet> getWeeks() {
507        if (iWeeks == null) {
508            String defaultDatePattern = getProperties().getProperty("DatePattern.CustomDatePattern", null);
509            if (defaultDatePattern == null){                
510                defaultDatePattern = getProperties().getProperty("DatePattern.Default");
511            }
512            BitSet fullTerm = null;
513            if (defaultDatePattern == null) {
514                // Take the date pattern that is being used most often
515                Map<Long, Integer> counter = new HashMap<Long, Integer>();
516                int max = 0; String name = null; Long id = null;
517                for (Lecture lecture: variables()) {
518                    if (lecture.isCommitted()) continue;
519                    for (TimeLocation time: lecture.timeLocations()) {
520                        if (time.getWeekCode() != null && time.getDatePatternId() != null) {
521                            int count = 1;
522                            if (counter.containsKey(time.getDatePatternId()))
523                                count += counter.get(time.getDatePatternId());
524                            counter.put(time.getDatePatternId(), count);
525                            if (count > max) {
526                                max = count; fullTerm = time.getWeekCode(); name = time.getDatePatternName(); id = time.getDatePatternId();
527                            }
528                        }
529                    }
530                }
531                sLogger.info("Using date pattern " + name + " (id " + id + ") as the default.");
532            } else {
533                // Create default date pattern
534                fullTerm = new BitSet(defaultDatePattern.length());
535                for (int i = 0; i < defaultDatePattern.length(); i++) {
536                    if (defaultDatePattern.charAt(i) == 49) {
537                        fullTerm.set(i);
538                    }
539                }
540            }
541            
542            if (fullTerm == null) return null;
543            
544            iWeeks = new ArrayList<BitSet>();
545            if (getProperties().getPropertyBoolean("DatePattern.ShiftWeeks", false)) {
546                // Cut date pattern into weeks (each week takes 7 consecutive bits, starting on the next positive bit)
547                for (int i = fullTerm.nextSetBit(0); i < fullTerm.length(); ) {
548                    if (!fullTerm.get(i)) {
549                        i++; continue;
550                    }
551                    BitSet w = new BitSet(i + 7);
552                    for (int j = 0; j < 7; j++)
553                        if (fullTerm.get(i + j)) w.set(i + j);
554                    iWeeks.add(w);
555                    i += 7;
556                }                
557            } else {
558                // Cut date pattern into weeks (each week takes 7 consecutive bits starting on the first bit of the default date pattern, no pauses between weeks)
559                for (int i = fullTerm.nextSetBit(0); i < fullTerm.length(); ) {
560                    BitSet w = new BitSet(i + 7);
561                    for (int j = 0; j < 7; j++)
562                        if (fullTerm.get(i + j)) w.set(i + j);
563                    iWeeks.add(w);
564                    i += 7;
565                }
566            }
567        }
568        return iWeeks;
569    }
570    
571    public List<StudentGroup> getStudentGroups() { return iStudentGroups; }
572    public void addStudentGroup(StudentGroup group) { iStudentGroups.add(group); }
573    
574    Map<Student, Set<Lecture>> iBestEnrollment = null;
575    @Override
576    public void saveBest(Assignment<Lecture, Placement> assignment) {
577        super.saveBest(assignment);
578        if (iOnFlySectioning) {
579            if (iBestEnrollment == null)
580                iBestEnrollment = new HashMap<Student, Set<Lecture>>();
581            else
582                iBestEnrollment.clear();
583            for (Student student: getAllStudents())
584                iBestEnrollment.put(student, new HashSet<Lecture>(student.getLectures()));
585        }
586    }
587    
588    /**
589     * Increment {@link JenrlConstraint} between the given two classes by the given student
590     */
591    protected void incJenrl(Assignment<Lecture, Placement> assignment, Student student, Lecture l1, Lecture l2) {
592        if (l1.equals(l2)) return;
593        JenrlConstraint jenrl = l1.jenrlConstraint(l2);
594        if (jenrl == null) {
595            jenrl = new JenrlConstraint();
596            jenrl.addVariable(l1);
597            jenrl.addVariable(l2);
598            addConstraint(jenrl);
599        }
600        jenrl.incJenrl(assignment, student);
601    }
602    
603    /**
604     * Decrement {@link JenrlConstraint} between the given two classes by the given student
605     */
606    protected void decJenrl(Assignment<Lecture, Placement> assignment, Student student, Lecture l1, Lecture l2) {
607        if (l1.equals(l2)) return;
608        JenrlConstraint jenrl = l1.jenrlConstraint(l2);
609        if (jenrl != null) {
610            jenrl.decJenrl(assignment, student);
611        }
612    }
613    
614    @Override
615    public void restoreBest(Assignment<Lecture, Placement> assignment) {
616        if (iOnFlySectioning && iBestEnrollment != null) {
617            
618            // unassign changed classes
619            for (Lecture lecture: variables()) {
620                Placement placement = assignment.getValue(lecture);
621                if (placement != null && !placement.equals(lecture.getBestAssignment()))
622                    assignment.unassign(0, lecture);
623            }
624            
625            for (Map.Entry<Student, Set<Lecture>> entry: iBestEnrollment.entrySet()) {
626                Student student = entry.getKey();
627                Set<Lecture> lectures = entry.getValue();
628                Set<Configuration> configs = new HashSet<Configuration>();
629                for (Lecture lecture: lectures)
630                    if (lecture.getConfiguration() != null) configs.add(lecture.getConfiguration());
631                
632                // drop student from classes that are not in the best enrollment
633                for (Lecture lecture: new ArrayList<Lecture>(student.getLectures())) {
634                    if (lectures.contains(lecture)) continue; // included in best
635                    for (Lecture other: student.getLectures())
636                        decJenrl(assignment, student, lecture, other);
637                    lecture.removeStudent(assignment, student);
638                    student.removeLecture(lecture);
639                    if (lecture.getConfiguration() != null && !configs.contains(lecture.getConfiguration()))
640                        student.removeConfiguration(lecture.getConfiguration());
641                }
642                
643                // add student to classes that are in the best enrollment
644                for (Lecture lecture: lectures) {
645                    if (student.getLectures().contains(lecture)) continue; // already in
646                    for (Lecture other: student.getLectures())
647                        incJenrl(assignment, student, lecture, other);
648                    lecture.addStudent(assignment, student);
649                    student.addLecture(lecture);
650                    student.addConfiguration(lecture.getConfiguration());
651                }
652            }
653            // remove empty joint enrollments
654            for (JenrlConstraint jenrl: new ArrayList<JenrlConstraint>(getJenrlConstraints())) {
655                if (jenrl.getNrStudents() == 0) {
656                    jenrl.getContext(assignment).unassigned(assignment, null);
657                    Object[] vars = jenrl.variables().toArray();
658                    for (int k = 0; k < vars.length; k++)
659                        jenrl.removeVariable((Lecture) vars[k]);
660                    removeConstraint(jenrl);
661                }
662            }
663        }
664        super.restoreBest(assignment);
665    }
666    
667    public boolean isAllowBreakHard() { return iAllowBreakHard; }
668}