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 * @author  Tomáš Müller
026 * @version StudentSct 1.3 (Student Sectioning)<br>
027 *          Copyright (C) 2007 - 2014 Tomáš Müller<br>
028 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
029 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
030 * <br>
031 *          This library is free software; you can redistribute it and/or modify
032 *          it under the terms of the GNU Lesser General Public License as
033 *          published by the Free Software Foundation; either version 3 of the
034 *          License, or (at your option) any later version. <br>
035 * <br>
036 *          This library is distributed in the hope that it will be useful, but
037 *          WITHOUT ANY WARRANTY; without even the implied warranty of
038 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
039 *          Lesser General Public License for more details. <br>
040 * <br>
041 *          You should have received a copy of the GNU Lesser General Public
042 *          License along with this library; if not see
043 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
044 */
045public class StudentChoiceOrder implements StudentOrder, Comparator<Student> {
046    private boolean iReverse = false;
047    private boolean iFast = true;
048    private boolean iCriticalOnly = false;
049    private RequestPriority iPriority = RequestPriority.Critical;
050    private HashMap<Config, Integer> iCache = new HashMap<Config, Integer>();
051
052    public StudentChoiceOrder(DataProperties config) {
053        iReverse = config.getPropertyBoolean("StudentChoiceOrder.Reverse", iReverse);
054        iFast = config.getPropertyBoolean("StudentChoiceOrder.Fast", iFast);
055        iCriticalOnly = config.getPropertyBoolean("StudentChoiceOrder.CriticalOnly", iCriticalOnly);
056    }
057
058    /** Is order reversed 
059     * @return true if the order is reversed
060     **/
061    public boolean isReverse() {
062        return iReverse;
063    }
064
065    /** Set reverse order 
066     * @param reverse true if students are to be in a reversed order
067     **/
068    public void setReverse(boolean reverse) {
069        iReverse = reverse;
070    }
071    
072    public boolean isCriticalOnly() { return iCriticalOnly; }
073    public void setCriticalOnly(boolean critOnly) { iCriticalOnly = critOnly; }
074    public void setRequestPriority(RequestPriority priority) { iPriority = priority; }
075    public RequestPriority getRequestPriority() { return iPriority; }
076
077    /** Order the given list of students */
078    @Override
079    public List<Student> order(List<Student> students) {
080        List<Student> ret = new ArrayList<Student>(students);
081        Collections.sort(ret, this);
082        return ret;
083    }
084
085    @Override
086    public int compare(Student s1, Student s2) {
087        if (s1.getPriority() != s2.getPriority()) return (s1.getPriority().ordinal() < s2.getPriority().ordinal() ? -1 : 1);
088        try {
089            int cmp = -Double.compare(avgNrChoices(s1), avgNrChoices(s2));
090            if (cmp != 0)
091                return (iReverse ? -1 : 1) * cmp;
092        } catch (Exception e) {
093            e.printStackTrace();
094        }
095        return (iReverse ? -1 : 1) * Double.compare(s1.getId(), s2.getId());
096    }
097
098    private int nrChoices(Config config, int idx, HashSet<Section> sections) {
099        if (iFast) {
100            int nrChoices = 1;
101            for (Subpart subpart: config.getSubparts()) {
102                if (subpart.getChildren().isEmpty())
103                    nrChoices *= subpart.getSections().size();
104            }
105            return nrChoices;
106        }
107        if (config.getSubparts().size() == idx) {
108            return 1;
109        } else {
110            Subpart subpart = config.getSubparts().get(idx);
111            int choicesThisSubpart = 0;
112            for (Section section : subpart.getSections()) {
113                if (section.getParent() != null && !sections.contains(section.getParent()))
114                    continue;
115                if (section.isOverlapping(sections))
116                    continue;
117                sections.add(section);
118                choicesThisSubpart += nrChoices(config, idx + 1, sections);
119                sections.remove(section);
120            }
121            return choicesThisSubpart;
122        }
123    }
124    
125    /** Average number of choices for each student 
126     * @param student given student
127     * @return average number of choices of the given student
128     **/
129    public double avgNrChoices(Student student) {
130        int nrRequests = 0;
131        int nrChoices = 0;
132        for (Request request : student.getRequests()) {
133            if (request instanceof CourseRequest) {
134                CourseRequest cr = (CourseRequest) request;
135                if (iCriticalOnly && (!iPriority.isCritical(cr) || cr.isAlternative())) continue;
136                for (Course course : cr.getCourses()) {
137                    for (Config config : course.getOffering().getConfigs()) {
138                        Integer nrChoicesThisCfg = iCache.get(config);
139                        if (nrChoicesThisCfg == null) {
140                            nrChoicesThisCfg = Integer.valueOf(nrChoices(config, 0, new HashSet<Section>()));
141                            iCache.put(config, nrChoicesThisCfg);
142                        }
143                        nrChoices += nrChoicesThisCfg.intValue();
144                    }
145                }
146                nrRequests++;
147            }
148        }
149        return (nrRequests == 0 ? 0.0 : ((double) nrChoices) / nrRequests);
150    }
151}