001package org.cpsolver.studentsct.heuristics.studentord; 002 003import org.cpsolver.ifs.util.DataProperties; 004import org.cpsolver.studentsct.model.CourseRequest; 005import org.cpsolver.studentsct.model.Request; 006import org.cpsolver.studentsct.model.Student; 007 008/** 009 * Return the given set of students in an order of average number of request groups of 010 * each student. If two students are involved in the same number of groups, the comparison 011 * falls down to the average number of choices of each student (students with less choices first). 012 * <br> 013 * 014 * @version StudentSct 1.3 (Student Sectioning)<br> 015 * Copyright (C) 2015 Tomas Muller<br> 016 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br> 017 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br> 018 * <br> 019 * This library is free software; you can redistribute it and/or modify 020 * it under the terms of the GNU Lesser General Public License as 021 * published by the Free Software Foundation; either version 3 of the 022 * License, or (at your option) any later version. <br> 023 * <br> 024 * This library is distributed in the hope that it will be useful, but 025 * WITHOUT ANY WARRANTY; without even the implied warranty of 026 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 027 * Lesser General Public License for more details. <br> 028 * <br> 029 * You should have received a copy of the GNU Lesser General Public 030 * License along with this library; if not see 031 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>. 032 */ 033public class StudentGroupsChoiceRealFirstOrder extends StudentChoiceOrder { 034 035 public StudentGroupsChoiceRealFirstOrder(DataProperties config) { 036 super(config); 037 } 038 039 public StudentGroupsChoiceRealFirstOrder() { 040 super(new DataProperties()); 041 setReverse(true); 042 } 043 044 @Override 045 public int compare(Student s1, Student s2) { 046 if (s1.isDummy()) { 047 if (!s2.isDummy()) 048 return 1; 049 } else if (s2.isDummy()) 050 return -1; 051 052 int cmp = -Double.compare(nrGroups(s1), nrGroups(s2)); 053 if (cmp != 0) 054 return cmp; 055 return super.compare(s1, s2); 056 } 057 058 /** 059 * Average number of request groups that the student is involved in 060 * @return number of groups / number of requests 061 */ 062 public double nrGroups(Student s) { 063 double nrGroups = 0.0; 064 for (Request r: s.getRequests()) { 065 if (r instanceof CourseRequest) 066 nrGroups += ((CourseRequest)r).getRequestGroups().size(); 067 } 068 return nrGroups / s.getRequests().size(); 069 } 070}