001 package net.sf.cpsolver.studentsct.heuristics.studentord; 002 003 import java.util.ArrayList; 004 import java.util.Collections; 005 import java.util.Comparator; 006 import java.util.HashSet; 007 import java.util.HashMap; 008 import java.util.List; 009 010 import net.sf.cpsolver.ifs.util.DataProperties; 011 import net.sf.cpsolver.studentsct.model.Config; 012 import net.sf.cpsolver.studentsct.model.Course; 013 import net.sf.cpsolver.studentsct.model.CourseRequest; 014 import net.sf.cpsolver.studentsct.model.Request; 015 import net.sf.cpsolver.studentsct.model.Section; 016 import net.sf.cpsolver.studentsct.model.Student; 017 import net.sf.cpsolver.studentsct.model.Subpart; 018 019 /** 020 * Return the given set of students in an order of average number of choices of 021 * each student (students with more choices first). 022 * 023 * @version StudentSct 1.2 (Student Sectioning)<br> 024 * Copyright (C) 2007 - 2010 Tomas Muller<br> 025 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br> 026 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br> 027 * <br> 028 * This library is free software; you can redistribute it and/or modify 029 * it under the terms of the GNU Lesser General Public License as 030 * published by the Free Software Foundation; either version 3 of the 031 * License, or (at your option) any later version. <br> 032 * <br> 033 * This library is distributed in the hope that it will be useful, but 034 * WITHOUT ANY WARRANTY; without even the implied warranty of 035 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 036 * Lesser General Public License for more details. <br> 037 * <br> 038 * You should have received a copy of the GNU Lesser General Public 039 * License along with this library; if not see 040 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>. 041 */ 042 public class StudentChoiceOrder implements StudentOrder, Comparator<Student> { 043 private boolean iReverse = false; 044 private HashMap<Config, Integer> iCache = new HashMap<Config, Integer>(); 045 046 public StudentChoiceOrder(DataProperties config) { 047 iReverse = config.getPropertyBoolean("StudentChoiceOrder.Reverse", iReverse); 048 } 049 050 /** Is order reversed */ 051 public boolean isReverse() { 052 return iReverse; 053 } 054 055 /** Set reverse order */ 056 public void setReverse(boolean reverse) { 057 iReverse = reverse; 058 } 059 060 /** Order the given list of students */ 061 @Override 062 public List<Student> order(List<Student> students) { 063 List<Student> ret = new ArrayList<Student>(students); 064 Collections.sort(ret, this); 065 return ret; 066 } 067 068 @Override 069 public int compare(Student s1, Student s2) { 070 try { 071 int cmp = -Double.compare(avgNrChoices(s1), avgNrChoices(s2)); 072 if (cmp != 0) 073 return (iReverse ? -1 : 1) * cmp; 074 } catch (Exception e) { 075 e.printStackTrace(); 076 } 077 return (iReverse ? -1 : 1) * Double.compare(s1.getId(), s2.getId()); 078 } 079 080 private int nrChoices(Config config, int idx, HashSet<Section> sections) { 081 if (config.getSubparts().size() == idx) { 082 return 1; 083 } else { 084 Subpart subpart = config.getSubparts().get(idx); 085 int choicesThisSubpart = 0; 086 for (Section section : subpart.getSections()) { 087 if (section.getParent() != null && !sections.contains(section.getParent())) 088 continue; 089 if (section.isOverlapping(sections)) 090 continue; 091 sections.add(section); 092 choicesThisSubpart += nrChoices(config, idx + 1, sections); 093 sections.remove(section); 094 } 095 return choicesThisSubpart; 096 } 097 } 098 099 /** Average number of choices for each student */ 100 public double avgNrChoices(Student student) { 101 int nrRequests = 0; 102 int nrChoices = 0; 103 for (Request request : student.getRequests()) { 104 if (request instanceof CourseRequest) { 105 CourseRequest cr = (CourseRequest) request; 106 for (Course course : cr.getCourses()) { 107 for (Config config : course.getOffering().getConfigs()) { 108 Integer nrChoicesThisCfg = iCache.get(config); 109 if (nrChoicesThisCfg == null) { 110 nrChoicesThisCfg = new Integer(nrChoices(config, 0, new HashSet<Section>())); 111 iCache.put(config, nrChoicesThisCfg); 112 } 113 nrChoices += nrChoicesThisCfg.intValue(); 114 } 115 } 116 nrRequests++; 117 } 118 } 119 return (nrRequests == 0 ? 0.0 : ((double) nrChoices) / nrRequests); 120 } 121 }