Examples with FreeTimeRequest org.cpsolver.studentsct.model.FreeTimeRequest used on opensource projects

Example 1 with FreeTimeRequest

use of org.cpsolver.studentsct.model.FreeTimeRequest in project cpsolver by UniTime.

the class StudentRequestXml method exportModel.

public static Document exportModel(Assignment<Request, Enrollment> assignment, StudentSectioningModel model) {
    Document document = DocumentHelper.createDocument();
    Element requestElement = document.addElement("request");
    requestElement.addAttribute("campus", model.getProperties().getProperty("Data.Initiative"));
    requestElement.addAttribute("year", model.getProperties().getProperty("Data.Year"));
    requestElement.addAttribute("term", model.getProperties().getProperty("Data.Term"));
    for (Student student : model.getStudents()) {
        Element studentElement = requestElement.addElement("student");
        studentElement.addAttribute("key", String.valueOf(student.getId()));
        Element courseRequestsElement = studentElement.addElement("updateCourseRequests");
        courseRequestsElement.addAttribute("commit", "true");
        Collections.sort(student.getRequests(), new Comparator<Request>() {

            @Override
            public int compare(Request r1, Request r2) {
                if (r1.isAlternative() != r2.isAlternative()) {
                    return (r1.isAlternative() ? 1 : -1);
                }
                return Double.compare(r1.getPriority(), r2.getPriority());
            }
        });
        boolean hasSchedule = false;
        for (Request request : student.getRequests()) {
            if (assignment.getValue(request) != null)
                hasSchedule = true;
            if (request instanceof FreeTimeRequest) {
                FreeTimeRequest ftReq = (FreeTimeRequest) request;
                Element ftReqElement = courseRequestsElement.addElement("freeTime");
                requestElement.addAttribute("days", ftReq.getTime().getDayHeader());
                int startSlot = ftReq.getTime().getStartSlot();
                int startTime = startSlot * Constants.SLOT_LENGTH_MIN + Constants.FIRST_SLOT_TIME_MIN;
                ftReqElement.addAttribute("startTime", s2zDF.format(startTime / 60) + s2zDF.format(startTime % 60));
                int endTime = startTime + ftReq.getTime().getLength() * Constants.SLOT_LENGTH_MIN - ftReq.getTime().getBreakTime();
                ftReqElement.addAttribute("endTime", s2zDF.format(endTime / 60) + s2zDF.format(endTime % 60));
                ftReqElement.addAttribute("length", String.valueOf(ftReq.getTime().getLength() * Constants.SLOT_LENGTH_MIN));
            } else {
                CourseRequest crReq = (CourseRequest) request;
                Element crReqElement = courseRequestsElement.addElement("courseOffering");
                Course course = crReq.getCourses().get(0);
                crReqElement.addAttribute("subjectArea", course.getSubjectArea());
                crReqElement.addAttribute("courseNumber", course.getCourseNumber());
                crReqElement.addAttribute("waitlist", crReq.isWaitlist() ? "true" : "false");
                crReqElement.addAttribute("alternative", crReq.isAlternative() ? "true" : "false");
                for (int i = 1; i < crReq.getCourses().size(); i++) {
                    Course altCourse = crReq.getCourses().get(i);
                    Element altCourseElement = crReqElement.addElement("alternative");
                    altCourseElement.addAttribute("subjectArea", altCourse.getSubjectArea());
                    altCourseElement.addAttribute("courseNumber", altCourse.getCourseNumber());
                }
            }
        }
        if (hasSchedule) {
            Element requestScheduleElement = studentElement.addElement("requestSchedule");
            requestScheduleElement.addAttribute("type", "commit");
            for (Request request : student.getRequests()) {
                if (request instanceof CourseRequest) {
                    CourseRequest crReq = (CourseRequest) request;
                    Enrollment enrollment = assignment.getValue(crReq);
                    if (enrollment == null)
                        continue;
                    Element crReqElement = requestScheduleElement.addElement("courseOffering");
                    Course course = enrollment.getCourse();
                    crReqElement.addAttribute("subjectArea", course.getSubjectArea());
                    crReqElement.addAttribute("courseNumber", course.getCourseNumber());
                    for (Section section : enrollment.getSections()) {
                        Element classEl = crReqElement.addElement("class");
                        classEl.addAttribute("id", section.getSubpart().getInstructionalType());
                        classEl.addAttribute("assignmentId", String.valueOf(section.getId()));
                    }
                }
            }
        }
    }
    return document;
}

Example 2 with FreeTimeRequest

use of org.cpsolver.studentsct.model.FreeTimeRequest in project cpsolver by UniTime.

the class InevitableStudentConflicts method check.

/** Check model for inevitable student conflicts 
     * @param assignment current assignment
     * @return true if there are no inevitable student conflicts
     **/
public boolean check(Assignment<Request, Enrollment> assignment) {
    sLog.info("Checking for inevitable student conflicts...");
    HashMap<TreeSet<Object>, Object[]> noGoods = new HashMap<TreeSet<Object>, Object[]>();
    long studentWithoutCompleteSchedule = 0;
    long inevitableRequests = 0;
    double inevitableRequestWeight = 0.0;
    long incompleteInevitableRequests = 0;
    double incompleteInevitableRequestWeight = 0.0;
    long total = 0;
    Comparator<Object> simpleCmp = new Comparator<Object>() {

        @Override
        public int compare(Object o1, Object o2) {
            return o1.toString().compareTo(o2.toString());
        }
    };
    HashSet<Request> requests2remove = new HashSet<Request>();
    for (Student student : getModel().getStudents()) {
        sLog.debug("  Checking " + (++total) + ". student " + student + "...");
        if (student.isComplete(assignment)) {
            for (Request request : student.getRequests()) {
                if (assignment.getValue(request) == null) {
                    inevitableRequests++;
                    inevitableRequestWeight += request.getWeight();
                }
            }
        } else {
            StudentCheck ch = new StudentCheck(student.getRequests());
            ch.check(assignment);
            if (!ch.isBestComplete()) {
                sLog.info("    Student " + student + " cannot have a complete schedule");
                studentWithoutCompleteSchedule++;
            }
            int idx = 0;
            for (Iterator<Request> f = student.getRequests().iterator(); f.hasNext(); idx++) {
                Request request = f.next();
                Enrollment enrollment = ch.getBestAssignment()[idx];
                if (enrollment == null) {
                    if (!ch.isBestComplete()) {
                        List<Request> noGood = noGood(assignment, student, ch, idx);
                        sLog.info("      Request " + request + " cannot be assigned");
                        for (Request r : noGood) {
                            sLog.debug("        " + r);
                            Collection<Enrollment> values = null;
                            if (r instanceof CourseRequest) {
                                values = ((CourseRequest) r).getEnrollmentsSkipSameTime(assignment);
                            } else {
                                values = request.computeEnrollments(assignment);
                            }
                            for (Enrollment en : values) {
                                sLog.debug("          " + enrollment2string(en));
                            }
                        }
                        if (iDeleteInevitable) {
                            // noGood.lastElement()
                            requests2remove.add(request);
                            sLog.info("        -- request " + request + " picked to be removed from the model");
                        }
                        TreeSet<Object> key = new TreeSet<Object>(simpleCmp);
                        for (Request r : noGood) {
                            if (r instanceof CourseRequest) {
                                key.add(((CourseRequest) r).getCourses().get(0));
                            } else {
                                key.add("Free " + ((FreeTimeRequest) r).getTime().getLongName(true));
                            }
                        }
                        Object[] counter = noGoods.get(key);
                        int ir = (counter == null ? 1 : ((Integer) counter[0]).intValue() + 1);
                        double irw = (counter == null ? 0.0 : ((Double) counter[1]).doubleValue()) + request.getWeight();
                        noGoods.put(key, new Object[] { new Integer(ir), new Double(irw) });
                        if (ch.canAssign(request, idx)) {
                            incompleteInevitableRequests++;
                            incompleteInevitableRequestWeight += request.getWeight();
                        }
                    }
                    inevitableRequests++;
                    inevitableRequestWeight += request.getWeight();
                }
            }
        }
    }
    for (Map.Entry<TreeSet<Object>, Object[]> entry : noGoods.entrySet()) {
        TreeSet<Object> noGood = entry.getKey();
        Object[] counter = entry.getValue();
        List<CSVFile.CSVField> fields = new ArrayList<CSVFile.CSVField>();
        String courseStr = "";
        for (Iterator<Object> j = noGood.iterator(); j.hasNext(); ) {
            Object x = j.next();
            if (x instanceof Course) {
                Course course = (Course) x;
                courseStr += course.getName();
            } else
                courseStr += x.toString();
            if (j.hasNext())
                courseStr += ", ";
        }
        fields.add(new CSVFile.CSVField(courseStr));
        fields.add(new CSVFile.CSVField(((Integer) counter[0]).intValue()));
        fields.add(new CSVFile.CSVField(((Double) counter[1]).doubleValue()));
        for (Iterator<Object> j = noGood.iterator(); j.hasNext(); ) {
            Object x = j.next();
            if (x instanceof Course) {
                Course course = (Course) x;
                List<Course> courses = new ArrayList<Course>(1);
                courses.add(course);
                CourseRequest cr = new CourseRequest(-1, 0, false, new Student(-1), courses, false, null);
                String field = course.getName();
                int idx = 0;
                for (Iterator<Enrollment> k = cr.getEnrollmentsSkipSameTime(assignment).iterator(); k.hasNext(); ) {
                    if (idx++ > 20) {
                        field += "\n ...";
                        break;
                    } else {
                        field += "\n  " + enrollment2string(k.next());
                    }
                }
                fields.add(new CSVFile.CSVField(field));
            } else
                fields.add(new CSVFile.CSVField(x.toString()));
        }
        iCSVFile.addLine(fields);
    }
    if (!requests2remove.isEmpty()) {
        for (Request request : requests2remove) {
            removeRequest(request);
        }
    }
    sLog.info("Students that can never obtain a complete schedule: " + studentWithoutCompleteSchedule);
    sLog.info("Inevitable student requests: " + inevitableRequests);
    sLog.info("Inevitable student request weight: " + inevitableRequestWeight);
    sLog.info("Inevitable student requests of students without a complete schedule: " + incompleteInevitableRequests);
    sLog.info("Inevitable student request weight of students without a complete schedule: " + incompleteInevitableRequestWeight);
    if (iCSVFile.getLines() != null)
        Collections.sort(iCSVFile.getLines(), new Comparator<CSVFile.CSVLine>() {

            @Override
            public int compare(CSVFile.CSVLine l1, CSVFile.CSVLine l2) {
                int cmp = Double.compare(l2.getField(1).toDouble(), l1.getField(1).toDouble());
                if (cmp != 0)
                    return cmp;
                return l1.getField(0).toString().compareTo(l2.getField(0).toString());
            }
        });
    return (inevitableRequests == 0);
}

Example 3 with FreeTimeRequest

use of org.cpsolver.studentsct.model.FreeTimeRequest in project cpsolver by UniTime.

the class TimeOverlapsCounter method allConflicts.

/**
     * The set of all conflicts ({@link Conflict} objects) of the given
     * enrollment and other enrollments that are assigned to the same student.
     * @param assignment current assignment
     * @param enrollment given enrollment
     * @return all conflicts of the given enrollment
     */
public Set<Conflict> allConflicts(Assignment<Request, Enrollment> assignment, Enrollment enrollment) {
    Set<Conflict> ret = new HashSet<Conflict>();
    if (enrollment.getRequest() instanceof FreeTimeRequest)
        return ret;
    for (Request request : enrollment.getStudent().getRequests()) {
        if (request.equals(enrollment.getRequest()))
            continue;
        Enrollment other = assignment.getValue(request);
        if (request instanceof FreeTimeRequest) {
            FreeTimeRequest ft = (FreeTimeRequest) request;
            ret.addAll(conflicts(enrollment, ft.createEnrollment()));
            continue;
        } else if (other != null) {
            ret.addAll(conflicts(enrollment, other));
        }
    }
    for (Unavailability unavailability : enrollment.getStudent().getUnavailabilities()) for (SctAssignment section : enrollment.getAssignments()) if (inConflict(section, unavailability))
        ret.add(new Conflict(enrollment.getStudent(), share(section, unavailability), enrollment, section, unavailability.createEnrollment(), unavailability));
    return ret;
}

Example 4 with FreeTimeRequest

use of org.cpsolver.studentsct.model.FreeTimeRequest in project cpsolver by UniTime.

the class Test method section.

public boolean section(Student original) {
    OnlineSectioningModel model = new TestModel(iModel.getProperties());
    model.setOverExpectedCriterion(iModel.getOverExpectedCriterion());
    Student student = new Student(original.getId());
    Hashtable<CourseRequest, Set<Section>> preferredSectionsForCourse = new Hashtable<CourseRequest, Set<Section>>();
    Map<Long, Section> classTable = new HashMap<Long, Section>();
    synchronized (iModel) {
        for (Request request : original.getRequests()) {
            Request clonnedRequest = addRequest(student, original, request, classTable, model);
            Enrollment enrollment = assignment().getValue(request);
            if (enrollment != null && enrollment.isCourseRequest()) {
                Set<Section> sections = new HashSet<Section>();
                for (Section section : enrollment.getSections()) sections.add(classTable.get(section.getId()));
                preferredSectionsForCourse.put((CourseRequest) clonnedRequest, sections);
            }
        }
    }
    model.addStudent(student);
    model.setDistanceConflict(new DistanceConflict(iModel.getDistanceConflict().getDistanceMetric(), model.getProperties()));
    model.setTimeOverlaps(new TimeOverlapsCounter(null, model.getProperties()));
    for (LinkedSections link : iModel.getLinkedSections()) {
        List<Section> sections = new ArrayList<Section>();
        for (Offering offering : link.getOfferings()) for (Subpart subpart : link.getSubparts(offering)) for (Section section : link.getSections(subpart)) {
            Section x = classTable.get(section.getId());
            if (x != null)
                sections.add(x);
        }
        if (sections.size() >= 2)
            model.addLinkedSections(link.isMustBeUsed(), sections);
    }
    OnlineSectioningSelection selection = null;
    if (model.getProperties().getPropertyBoolean("StudentWeights.MultiCriteria", true)) {
        selection = new MultiCriteriaBranchAndBoundSelection(iModel.getProperties());
    } else {
        selection = new SuggestionSelection(model.getProperties());
    }
    selection.setModel(model);
    selection.setPreferredSections(preferredSectionsForCourse);
    selection.setRequiredSections(new Hashtable<CourseRequest, Set<Section>>());
    selection.setRequiredFreeTimes(new HashSet<FreeTimeRequest>());
    long t0 = JProf.currentTimeMillis();
    Assignment<Request, Enrollment> newAssignment = new AssignmentMap<Request, Enrollment>();
    BranchBoundNeighbour neighbour = selection.select(newAssignment, student);
    long time = JProf.currentTimeMillis() - t0;
    inc("[C] CPU Time", time);
    if (neighbour == null) {
        inc("[F] Failure");
    } else {
        if (iSuggestions) {
            StudentPreferencePenalties penalties = new StudentPreferencePenalties(StudentPreferencePenalties.sDistTypePreference);
            double maxOverExpected = 0;
            int assigned = 0;
            double penalty = 0.0;
            Hashtable<CourseRequest, Set<Section>> enrollments = new Hashtable<CourseRequest, Set<Section>>();
            List<RequestSectionPair> pairs = new ArrayList<RequestSectionPair>();
            for (int i = 0; i < neighbour.getAssignment().length; i++) {
                Enrollment enrl = neighbour.getAssignment()[i];
                if (enrl != null && enrl.isCourseRequest() && enrl.getAssignments() != null) {
                    assigned++;
                    for (Section section : enrl.getSections()) {
                        maxOverExpected += model.getOverExpected(newAssignment, section, enrl.getRequest());
                        pairs.add(new RequestSectionPair(enrl.variable(), section));
                    }
                    enrollments.put((CourseRequest) enrl.variable(), enrl.getSections());
                    penalty += penalties.getPenalty(enrl);
                }
            }
            penalty /= assigned;
            inc("[S] Initial Penalty", penalty);
            double nrSuggestions = 0.0, nrAccepted = 0.0, totalSuggestions = 0.0, nrTries = 0.0;
            for (int i = 0; i < pairs.size(); i++) {
                RequestSectionPair pair = pairs.get(i);
                SuggestionsBranchAndBound suggestionBaB = null;
                if (model.getProperties().getPropertyBoolean("StudentWeights.MultiCriteria", true)) {
                    suggestionBaB = new MultiCriteriaBranchAndBoundSuggestions(model.getProperties(), student, newAssignment, new Hashtable<CourseRequest, Set<Section>>(), new HashSet<FreeTimeRequest>(), enrollments, pair.getRequest(), pair.getSection(), null, maxOverExpected, iModel.getProperties().getPropertyBoolean("StudentWeights.PriorityWeighting", true));
                } else {
                    suggestionBaB = new SuggestionsBranchAndBound(model.getProperties(), student, newAssignment, new Hashtable<CourseRequest, Set<Section>>(), new HashSet<FreeTimeRequest>(), enrollments, pair.getRequest(), pair.getSection(), null, maxOverExpected);
                }
                long x0 = JProf.currentTimeMillis();
                TreeSet<SuggestionsBranchAndBound.Suggestion> suggestions = suggestionBaB.computeSuggestions();
                inc("[S] Suggestion CPU Time", JProf.currentTimeMillis() - x0);
                totalSuggestions += suggestions.size();
                if (!suggestions.isEmpty())
                    nrSuggestions += 1.0;
                nrTries += 1.0;
                SuggestionsBranchAndBound.Suggestion best = null;
                for (SuggestionsBranchAndBound.Suggestion suggestion : suggestions) {
                    int a = 0;
                    double p = 0.0;
                    for (int j = 0; j < suggestion.getEnrollments().length; j++) {
                        Enrollment e = suggestion.getEnrollments()[j];
                        if (e != null && e.isCourseRequest() && e.getAssignments() != null) {
                            p += penalties.getPenalty(e);
                            a++;
                        }
                    }
                    p /= a;
                    if (a > assigned || (assigned == a && p < penalty)) {
                        best = suggestion;
                    }
                }
                if (best != null) {
                    nrAccepted += 1.0;
                    Enrollment[] e = best.getEnrollments();
                    for (int j = 0; j < e.length; j++) if (e[j] != null && e[j].getAssignments() == null)
                        e[j] = null;
                    neighbour = new BranchBoundNeighbour(student, best.getValue(), e);
                    assigned = 0;
                    penalty = 0.0;
                    enrollments.clear();
                    pairs.clear();
                    for (int j = 0; j < neighbour.getAssignment().length; j++) {
                        Enrollment enrl = neighbour.getAssignment()[j];
                        if (enrl != null && enrl.isCourseRequest() && enrl.getAssignments() != null) {
                            assigned++;
                            for (Section section : enrl.getSections()) pairs.add(new RequestSectionPair(enrl.variable(), section));
                            enrollments.put((CourseRequest) enrl.variable(), enrl.getSections());
                            penalty += penalties.getPenalty(enrl);
                        }
                    }
                    penalty /= assigned;
                    inc("[S] Improved Penalty", penalty);
                }
            }
            inc("[S] Final Penalty", penalty);
            if (nrSuggestions > 0) {
                inc("[S] Classes with suggestion", nrSuggestions);
                inc("[S] Avg. # of suggestions", totalSuggestions / nrSuggestions);
                inc("[S] Suggestion acceptance rate [%]", nrAccepted / nrSuggestions);
            } else {
                inc("[S] Student with no suggestions available", 1.0);
            }
            if (!pairs.isEmpty())
                inc("[S] Probability that a class has suggestions [%]", nrSuggestions / nrTries);
        }
        List<Enrollment> enrollments = new ArrayList<Enrollment>();
        i: for (int i = 0; i < neighbour.getAssignment().length; i++) {
            Request request = original.getRequests().get(i);
            Enrollment clonnedEnrollment = neighbour.getAssignment()[i];
            if (clonnedEnrollment != null && clonnedEnrollment.getAssignments() != null) {
                if (request instanceof FreeTimeRequest) {
                    enrollments.add(((FreeTimeRequest) request).createEnrollment());
                } else {
                    for (Course course : ((CourseRequest) request).getCourses()) if (course.getId() == clonnedEnrollment.getCourse().getId())
                        for (Config config : course.getOffering().getConfigs()) if (config.getId() == clonnedEnrollment.getConfig().getId()) {
                            Set<Section> assignments = new HashSet<Section>();
                            for (Subpart subpart : config.getSubparts()) for (Section section : subpart.getSections()) {
                                if (clonnedEnrollment.getSections().contains(section)) {
                                    assignments.add(section);
                                }
                            }
                            Reservation reservation = null;
                            if (clonnedEnrollment.getReservation() != null) {
                                for (Reservation r : course.getOffering().getReservations()) if (r.getId() == clonnedEnrollment.getReservation().getId()) {
                                    reservation = r;
                                    break;
                                }
                            }
                            enrollments.add(new Enrollment(request, clonnedEnrollment.getPriority(), course, config, assignments, reservation));
                            continue i;
                        }
                }
            }
        }
        synchronized (iModel) {
            for (Request r : original.getRequests()) {
                Enrollment e = assignment().getValue(r);
                r.setInitialAssignment(e);
                if (e != null)
                    updateSpace(assignment(), e, true);
            }
            for (Request r : original.getRequests()) if (assignment().getValue(r) != null)
                assignment().unassign(0, r);
            boolean fail = false;
            for (Enrollment enrl : enrollments) {
                if (iModel.conflictValues(assignment(), enrl).isEmpty()) {
                    assignment().assign(0, enrl);
                } else {
                    fail = true;
                    break;
                }
            }
            if (fail) {
                for (Request r : original.getRequests()) if (assignment().getValue(r) != null)
                    assignment().unassign(0, r);
                for (Request r : original.getRequests()) if (r.getInitialAssignment() != null)
                    assignment().assign(0, r.getInitialAssignment());
                for (Request r : original.getRequests()) if (assignment().getValue(r) != null)
                    updateSpace(assignment(), assignment().getValue(r), false);
            } else {
                for (Enrollment enrl : enrollments) updateSpace(assignment(), enrl, false);
            }
            if (fail)
                return false;
        }
        neighbour.assign(newAssignment, 0);
        int a = 0, u = 0, np = 0, zp = 0, pp = 0, cp = 0;
        double over = 0;
        double p = 0.0;
        for (Request r : student.getRequests()) {
            if (r instanceof CourseRequest) {
                Enrollment e = newAssignment.getValue(r);
                if (e != null) {
                    for (Section s : e.getSections()) {
                        if (s.getPenalty() < 0.0)
                            np++;
                        if (s.getPenalty() == 0.0)
                            zp++;
                        if (s.getPenalty() > 0.0)
                            pp++;
                        if (s.getLimit() > 0) {
                            p += s.getPenalty();
                            cp++;
                        }
                        over += model.getOverExpected(newAssignment, s, r);
                    }
                    a++;
                } else {
                    u++;
                }
            }
        }
        inc("[A] Student");
        if (over > 0.0)
            inc("[O] Over", over);
        if (a > 0)
            inc("[A] Assigned", a);
        if (u > 0)
            inc("[A] Not Assigned", u);
        inc("[V] Value", neighbour.value(newAssignment));
        if (zp > 0)
            inc("[P] Zero penalty", zp);
        if (np > 0)
            inc("[P] Negative penalty", np);
        if (pp > 0)
            inc("[P] Positive penalty", pp);
        if (cp > 0)
            inc("[P] Average penalty", p / cp);
    }
    inc("[T0] Time <10ms", time < 10 ? 1 : 0);
    inc("[T1] Time <100ms", time < 100 ? 1 : 0);
    inc("[T2] Time <250ms", time < 250 ? 1 : 0);
    inc("[T3] Time <500ms", time < 500 ? 1 : 0);
    inc("[T4] Time <1s", time < 1000 ? 1 : 0);
    inc("[T5] Time >=1s", time >= 1000 ? 1 : 0);
    return true;
}

Example 5 with FreeTimeRequest

use of org.cpsolver.studentsct.model.FreeTimeRequest in project cpsolver by UniTime.

the class OnlineSectioningCriterion method canImprove.

@Override
public boolean canImprove(Assignment<Request, Enrollment> assignment, int maxIdx, Enrollment[] current, Enrollment[] best) {
    // 0. best priority & alternativity ignoring free time requests
    int alt = 0;
    boolean ft = false;
    for (int idx = 0; idx < current.length; idx++) {
        if (isFreeTime(idx)) {
            ft = true;
            continue;
        }
        Request request = getRequest(idx);
        if (idx < maxIdx) {
            if (best[idx] != null) {
                if (current[idx] == null)
                    // higher priority request assigned
                    return false;
                if (best[idx].getPriority() < current[idx].getPriority())
                    // less alternative request assigned
                    return false;
                if (request.isAlternative())
                    alt--;
            } else {
                if (current[idx] != null)
                    // higher priority request assigned
                    return true;
                if (!request.isAlternative())
                    alt++;
            }
        } else {
            if (best[idx] != null) {
                if (best[idx].getPriority() > 0)
                    // alternativity can be improved
                    return true;
            } else {
                if (!request.isAlternative() || alt > 0)
                    // priority can be improved
                    return true;
            }
        }
    }
    // 0.5. avoid course time overlaps & unavailability overlaps
    if (getModel().getTimeOverlaps() != null) {
        int bestTimeOverlaps = 0, currentTimeOverlaps = 0;
        for (int idx = 0; idx < current.length; idx++) {
            if (best[idx] != null && best[idx].getRequest() instanceof CourseRequest) {
                for (int x = 0; x < idx; x++) {
                    if (best[x] != null && best[x].getRequest() instanceof CourseRequest)
                        bestTimeOverlaps += getModel().getTimeOverlaps().nrConflicts(best[x], best[idx]);
                }
            }
            if (current[idx] != null && idx < maxIdx && current[idx].getRequest() instanceof CourseRequest) {
                for (int x = 0; x < idx; x++) {
                    if (current[x] != null && current[x].getRequest() instanceof CourseRequest)
                        currentTimeOverlaps += getModel().getTimeOverlaps().nrConflicts(current[x], current[idx]);
                }
            }
        }
        for (int idx = 0; idx < current.length; idx++) {
            if (best[idx] != null && best[idx].getAssignments() != null && best[idx].isCourseRequest()) {
                bestTimeOverlaps += getModel().getTimeOverlaps().nrNotAvailableTimeConflicts(best[idx]);
            }
            if (current[idx] != null && idx < maxIdx && current[idx].getAssignments() != null && current[idx].isCourseRequest()) {
                currentTimeOverlaps += getModel().getTimeOverlaps().nrNotAvailableTimeConflicts(current[idx]);
            }
        }
        if (currentTimeOverlaps < bestTimeOverlaps)
            return true;
        if (bestTimeOverlaps < currentTimeOverlaps)
            return false;
    }
    // 1. maximize number of penalties
    double bestPenalties = 0, currentPenalties = 0;
    for (int idx = 0; idx < current.length; idx++) {
        if (best[idx] != null) {
            for (Section section : best[idx].getSections()) bestPenalties += getModel().getOverExpected(assignment, section, best[idx].getRequest());
        }
        if (current[idx] != null && idx < maxIdx) {
            for (Section section : current[idx].getSections()) currentPenalties += getModel().getOverExpected(assignment, section, current[idx].getRequest());
        }
    }
    if (currentPenalties < bestPenalties)
        return true;
    if (bestPenalties < currentPenalties)
        return false;
    // 2. best priority & alternativity including free times
    if (ft) {
        alt = 0;
        for (int idx = 0; idx < current.length; idx++) {
            Request request = getStudent().getRequests().get(idx);
            if (idx < maxIdx) {
                if (best[idx] != null) {
                    if (current[idx] == null)
                        // higher priority request assigned
                        return false;
                    if (best[idx].getPriority() < current[idx].getPriority())
                        // less alternative request assigned
                        return false;
                    if (request.isAlternative())
                        alt--;
                } else {
                    if (current[idx] != null)
                        // higher priority request assigned
                        return true;
                    if (request instanceof CourseRequest && !request.isAlternative())
                        alt++;
                }
            } else {
                if (best[idx] != null) {
                    if (best[idx].getPriority() > 0)
                        // alternativity can be improved
                        return true;
                } else {
                    if (!request.isAlternative() || alt > 0)
                        // priority can be improved
                        return true;
                }
            }
        }
    }
    // 3. maximize selection
    int bestSelected = 0, currentSelected = 0;
    for (int idx = 0; idx < current.length; idx++) {
        if (best[idx] != null && best[idx].isCourseRequest()) {
            Set<Section> preferred = getPreferredSections(best[idx].getRequest());
            if (preferred != null && !preferred.isEmpty()) {
                for (Section section : best[idx].getSections()) if (preferred.contains(section)) {
                    if (idx < maxIdx)
                        bestSelected++;
                } else if (idx >= maxIdx)
                    bestSelected--;
            }
        }
        if (current[idx] != null && idx < maxIdx && current[idx].isCourseRequest()) {
            Set<Section> preferred = getPreferredSections(current[idx].getRequest());
            if (preferred != null && !preferred.isEmpty()) {
                for (Section section : current[idx].getSections()) if (preferred.contains(section))
                    currentSelected++;
            }
        }
    }
    if (currentSelected > bestSelected)
        return true;
    if (bestSelected > currentSelected)
        return false;
    // 3.5 maximize preferences
    double bestSelectedConfigs = 0, currentSelectedConfigs = 0;
    double bestSelectedSections = 0, currentSelectedSections = 0;
    for (int idx = 0; idx < current.length; idx++) {
        if (best[idx] != null && best[idx].getAssignments() != null && best[idx].isCourseRequest()) {
            bestSelectedSections += best[idx].percentSelectedSameSection();
            bestSelectedConfigs += best[idx].percentSelectedSameConfig();
            if (idx >= maxIdx) {
                bestSelectedSections -= 1.0;
                bestSelectedConfigs -= 1.0;
            }
        }
        if (current[idx] != null && idx < maxIdx && current[idx].getAssignments() != null && current[idx].isCourseRequest()) {
            currentSelectedSections += current[idx].percentSelectedSameSection();
            currentSelectedConfigs += current[idx].percentSelectedSameConfig();
        }
    }
    if (0.3 * currentSelectedConfigs + 0.7 * currentSelectedSections > 0.3 * bestSelectedConfigs + 0.7 * bestSelectedSections)
        return true;
    if (0.3 * bestSelectedConfigs + 0.7 * bestSelectedSections > 0.3 * currentSelectedConfigs + 0.7 * currentSelectedSections)
        return false;
    // 4. avoid time overlaps
    if (getModel().getTimeOverlaps() != null) {
        int bestTimeOverlaps = 0, currentTimeOverlaps = 0;
        for (int idx = 0; idx < current.length; idx++) {
            if (best[idx] != null) {
                for (int x = 0; x < idx; x++) {
                    if (best[x] != null)
                        bestTimeOverlaps += getModel().getTimeOverlaps().nrConflicts(best[x], best[idx]);
                    else if (getStudent().getRequests().get(x) instanceof FreeTimeRequest)
                        bestTimeOverlaps += getModel().getTimeOverlaps().nrConflicts(((FreeTimeRequest) getStudent().getRequests().get(x)).createEnrollment(), best[idx]);
                }
            }
            if (current[idx] != null && idx < maxIdx) {
                for (int x = 0; x < idx; x++) {
                    if (current[x] != null)
                        currentTimeOverlaps += getModel().getTimeOverlaps().nrConflicts(current[x], current[idx]);
                    else if (getStudent().getRequests().get(x) instanceof FreeTimeRequest)
                        currentTimeOverlaps += getModel().getTimeOverlaps().nrConflicts(((FreeTimeRequest) getStudent().getRequests().get(x)).createEnrollment(), current[idx]);
                }
            }
        }
        for (int idx = 0; idx < current.length; idx++) {
            if (best[idx] != null && best[idx].getAssignments() != null && best[idx].isCourseRequest()) {
                bestTimeOverlaps += getModel().getTimeOverlaps().nrNotAvailableTimeConflicts(best[idx]);
            }
            if (current[idx] != null && idx < maxIdx && current[idx].getAssignments() != null && current[idx].isCourseRequest()) {
                currentTimeOverlaps += getModel().getTimeOverlaps().nrNotAvailableTimeConflicts(current[idx]);
            }
        }
        if (currentTimeOverlaps < bestTimeOverlaps)
            return true;
        if (bestTimeOverlaps < currentTimeOverlaps)
            return false;
    }
    // 5. avoid distance conflicts
    if (getModel().getDistanceConflict() != null) {
        int bestDistanceConf = 0, currentDistanceConf = 0;
        for (int idx = 0; idx < current.length; idx++) {
            if (best[idx] != null) {
                for (int x = 0; x < idx; x++) {
                    if (best[x] != null)
                        bestDistanceConf += getModel().getDistanceConflict().nrConflicts(best[x], best[idx]);
                }
            }
            if (current[idx] != null && idx < maxIdx) {
                for (int x = 0; x < idx; x++) {
                    if (current[x] != null)
                        currentDistanceConf += getModel().getDistanceConflict().nrConflicts(current[x], current[idx]);
                }
            }
        }
        if (currentDistanceConf < bestDistanceConf)
            return true;
        if (bestDistanceConf < currentDistanceConf)
            return false;
    }
    // 6. avoid no-time sections
    int bestNoTime = 0, currentNoTime = 0;
    for (int idx = 0; idx < current.length; idx++) {
        if (best[idx] != null) {
            for (Section section : best[idx].getSections()) if (section.getTime() == null)
                bestNoTime++;
        }
        if (current[idx] != null && idx < maxIdx) {
            for (Section section : current[idx].getSections()) if (section.getTime() == null)
                currentNoTime++;
        }
    }
    if (currentNoTime < bestNoTime)
        return true;
    if (bestNoTime < currentNoTime)
        return false;
    // 7. balance sections
    double bestUnavailableSize = 0.0, currentUnavailableSize = 0.0;
    int bestAltSectionsWithLimit = 0, currentAltSectionsWithLimit = 0;
    for (int idx = 0; idx < current.length; idx++) {
        if (best[idx] != null) {
            for (Section section : best[idx].getSections()) {
                Subpart subpart = section.getSubpart();
                // skip unlimited and single section subparts
                if (subpart.getSections().size() <= 1 || subpart.getLimit() <= 0)
                    continue;
                // average size
                double averageSize = ((double) subpart.getLimit()) / subpart.getSections().size();
                // section is below average
                if (section.getLimit() < averageSize)
                    bestUnavailableSize += (averageSize - section.getLimit()) / averageSize;
                bestAltSectionsWithLimit++;
            }
        }
        if (current[idx] != null && idx < maxIdx) {
            for (Section section : current[idx].getSections()) {
                Subpart subpart = section.getSubpart();
                // skip unlimited and single section subparts
                if (subpart.getSections().size() <= 1 || subpart.getLimit() <= 0)
                    continue;
                // average size
                double averageSize = ((double) subpart.getLimit()) / subpart.getSections().size();
                // section is below average
                if (section.getLimit() < averageSize)
                    currentUnavailableSize += (averageSize - section.getLimit()) / averageSize;
                currentAltSectionsWithLimit++;
            }
        }
    }
    double bestUnavailableSizeFraction = (bestUnavailableSize > 0 ? bestUnavailableSize / bestAltSectionsWithLimit : 0.0);
    double currentUnavailableSizeFraction = (currentUnavailableSize > 0 ? currentUnavailableSize / currentAltSectionsWithLimit : 0.0);
    if (currentUnavailableSizeFraction < bestUnavailableSizeFraction)
        return true;
    if (bestUnavailableSizeFraction < currentUnavailableSizeFraction)
        return false;
    // 8. average penalty sections
    double bestPenalty = 0.0, currentPenalty = 0.0;
    for (int idx = 0; idx < current.length; idx++) {
        if (best[idx] != null) {
            for (Section section : best[idx].getSections()) bestPenalty += section.getPenalty();
            if (idx >= maxIdx && best[idx].isCourseRequest())
                bestPenalty -= ((CourseRequest) best[idx].getRequest()).getMinPenalty();
        }
        if (current[idx] != null && idx < maxIdx) {
            for (Section section : current[idx].getSections()) currentPenalty += section.getPenalty();
        }
    }
    if (currentPenalty < bestPenalty)
        return true;
    if (bestPenalty < currentPenalty)
        return false;
    return true;
}