    001package org.cpsolver.studentsct.heuristics.studentord;
    002
    003import java.util.ArrayList;
    004import java.util.Collections;
    005import java.util.Comparator;
    006import java.util.HashSet;
    007import java.util.HashMap;
    008import java.util.List;
    009
    010import org.cpsolver.ifs.util.DataProperties;
    011import org.cpsolver.studentsct.model.Config;
    012import org.cpsolver.studentsct.model.Course;
    013import org.cpsolver.studentsct.model.CourseRequest;
    014import org.cpsolver.studentsct.model.Request;
    015import org.cpsolver.studentsct.model.Request.RequestPriority;
    016import org.cpsolver.studentsct.model.Section;
    017import org.cpsolver.studentsct.model.Student;
    018import org.cpsolver.studentsct.model.Subpart;
    019
    020
    021/**
    022 * Return the given set of students in an order of average number of choices of
    023 * each student (students with more choices first).
    024 *
    025 * @version StudentSct 1.3 (Student Sectioning)<br>
    026 *          Copyright (C) 2007 - 2014 Tomáš Müller<br>
    027 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    028 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    029 * <br>
    030 *          This library is free software; you can redistribute it and/or modify
    031 *          it under the terms of the GNU Lesser General Public License as
    032 *          published by the Free Software Foundation; either version 3 of the
    033 *          License, or (at your option) any later version. <br>
    034 * <br>
    035 *          This library is distributed in the hope that it will be useful, but
    036 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    037 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    038 *          Lesser General Public License for more details. <br>
    039 * <br>
    040 *          You should have received a copy of the GNU Lesser General Public
    041 *          License along with this library; if not see
    042 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
    043 */
    044public class StudentChoiceOrder implements StudentOrder, Comparator<Student> {
    045    private boolean iReverse = false;
    046    private boolean iFast = true;
    047    private boolean iCriticalOnly = false;
    048    private RequestPriority iPriority = RequestPriority.Critical;
    049    private HashMap<Config, Integer> iCache = new HashMap<Config, Integer>();
    050
    051    public StudentChoiceOrder(DataProperties config) {
    052        iReverse = config.getPropertyBoolean("StudentChoiceOrder.Reverse", iReverse);
    053        iFast = config.getPropertyBoolean("StudentChoiceOrder.Fast", iFast);
    054        iCriticalOnly = config.getPropertyBoolean("StudentChoiceOrder.CriticalOnly", iCriticalOnly);
    055    }
    056
    057    /** Is order reversed
    058     * @return true if the order is reversed
    059     **/
    060    public boolean isReverse() {
    061        return iReverse;
    062    }
    063
    064    /** Set reverse order
    065     * @param reverse true if students are to be in a reversed order
    066     **/
    067    public void setReverse(boolean reverse) {
    068        iReverse = reverse;
    069    }
    070
    071    public boolean isCriticalOnly() { return iCriticalOnly; }
    072    public void setCriticalOnly(boolean critOnly) { iCriticalOnly = critOnly; }
    073    public void setRequestPriority(RequestPriority priority) { iPriority = priority; }
    074    public RequestPriority getRequestPriority() { return iPriority; }
    075
    076    /** Order the given list of students */
    077    @Override
    078    public List<Student> order(List<Student> students) {
    079        List<Student> ret = new ArrayList<Student>(students);
    080        Collections.sort(ret, this);
    081        return ret;
    082    }
    083
    084    @Override
    085    public int compare(Student s1, Student s2) {
    086        if (s1.getPriority() != s2.getPriority()) return (s1.getPriority().ordinal() < s2.getPriority().ordinal() ? -1 : 1);
    087        try {
    088            int cmp = -Double.compare(avgNrChoices(s1), avgNrChoices(s2));
    089            if (cmp != 0)
    090                return (iReverse ? -1 : 1) * cmp;
    091        } catch (Exception e) {
    092            e.printStackTrace();
    093        }
    094        return (iReverse ? -1 : 1) * Double.compare(s1.getId(), s2.getId());
    095    }
    096
    097    private int nrChoices(Config config, int idx, HashSet<Section> sections) {
    098        if (iFast) {
    099            int nrChoices = 1;
    100            for (Subpart subpart: config.getSubparts()) {
    101                if (subpart.getChildren().isEmpty())
    102                    nrChoices *= subpart.getSections().size();
    103            }
    104            return nrChoices;
    105        }
    106        if (config.getSubparts().size() == idx) {
    107            return 1;
    108        } else {
    109            Subpart subpart = config.getSubparts().get(idx);
    110            int choicesThisSubpart = 0;
    111            for (Section section : subpart.getSections()) {
    112                if (section.getParent() != null && !sections.contains(section.getParent()))
    113                    continue;
    114                if (section.isOverlapping(sections))
    115                    continue;
    116                sections.add(section);
    117                choicesThisSubpart += nrChoices(config, idx + 1, sections);
    118                sections.remove(section);
    119            }
    120            return choicesThisSubpart;
    121        }
    122    }
    123
    124    /** Average number of choices for each student
    125     * @param student given student
    126     * @return average number of choices of the given student
    127     **/
    128    public double avgNrChoices(Student student) {
    129        int nrRequests = 0;
    130        int nrChoices = 0;
    131        for (Request request : student.getRequests()) {
    132            if (request instanceof CourseRequest) {
    133                CourseRequest cr = (CourseRequest) request;
    134                if (iCriticalOnly && (!iPriority.isCritical(cr) || cr.isAlternative())) continue;
    135                for (Course course : cr.getCourses()) {
    136                    for (Config config : course.getOffering().getConfigs()) {
    137                        Integer nrChoicesThisCfg = iCache.get(config);
    138                        if (nrChoicesThisCfg == null) {
    139                            nrChoicesThisCfg = new Integer(nrChoices(config, 0, new HashSet<Section>()));
    140                            iCache.put(config, nrChoicesThisCfg);
    141                        }
    142                        nrChoices += nrChoicesThisCfg.intValue();
    143                    }
    144                }
    145                nrRequests++;
    146            }
    147        }
    148        return (nrRequests == 0 ? 0.0 : ((double) nrChoices) / nrRequests);
    149    }
    150}