001 package net.sf.cpsolver.coursett.constraint;
002
003 import java.util.Set;
004
005 import net.sf.cpsolver.coursett.model.Lecture;
006 import net.sf.cpsolver.coursett.model.Placement;
007 import net.sf.cpsolver.coursett.model.Student;
008 import net.sf.cpsolver.coursett.model.TimeLocation;
009 import net.sf.cpsolver.coursett.model.TimetableModel;
010 import net.sf.cpsolver.ifs.model.BinaryConstraint;
011 import net.sf.cpsolver.ifs.model.Value;
012 import net.sf.cpsolver.ifs.model.Variable;
013 import net.sf.cpsolver.ifs.util.ToolBox;
014
015 /**
016 * Join student enrollment constraint.
017 * <br>
018 * This constraint is placed between all pairs of classes where there is at least one student attending both classes.
019 * It represents a number of student conflicts (number of joined enrollments), if the given two classes overlap in time.
020 * <br>
021 * Also, it dynamically maintains the counter of all student conflicts. It is a soft constraint.
022 *
023 *
024 * @version
025 * CourseTT 1.1 (University Course Timetabling)<br>
026 * Copyright (C) 2006 Tomáš Müller<br>
027 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
028 * Lazenska 391, 76314 Zlin, Czech Republic<br>
029 * <br>
030 * This library is free software; you can redistribute it and/or
031 * modify it under the terms of the GNU Lesser General Public
032 * License as published by the Free Software Foundation; either
033 * version 2.1 of the License, or (at your option) any later version.
034 * <br><br>
035 * This library is distributed in the hope that it will be useful,
036 * but 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.
039 * <br><br>
040 * You should have received a copy of the GNU Lesser General Public
041 * License along with this library; if not, write to the Free Software
042 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
043 */
044
045 public class JenrlConstraint extends BinaryConstraint {
046 private static org.apache.log4j.Logger sLogger = org.apache.log4j.Logger.getLogger(JenrlConstraint.class);
047 private double iJenrl = 0.0;
048 private int iNrStrudents = 0;
049 private boolean iAdded = false;
050 private boolean iAddedDistance = false;
051
052 /** Constructor
053 */
054 public JenrlConstraint() {
055 super();
056 }
057
058 public void computeConflicts(Value value, Set conflicts) {
059 }
060
061 public boolean inConflict(Value value) {
062 return false;
063 }
064
065 public boolean isConsistent(Value value1, Value value2) {
066 return true;
067 }
068
069 public void unassigned(long iteration, Value value) {
070 super.unassigned(iteration, value);
071 if (iAdded) {
072 ((TimetableModel)getModel()).getViolatedStudentConflictsCounter().dec((long)Math.ceil(iJenrl));
073 if (areStudentConflictsHard())
074 ((TimetableModel)getModel()).getViolatedHardStudentConflictsCounter().dec((long)Math.ceil(iJenrl));
075 iAdded=false;
076 ((Lecture)first()).removeActiveJenrl(this);
077 ((Lecture)second()).removeActiveJenrl(this);
078 }
079 if (iAddedDistance) {
080 ((TimetableModel)getModel()).getViolatedDistanceStudentConflictsCounter().dec((long)Math.ceil(iJenrl));
081 iAddedDistance = false;
082 }
083 }
084
085 /** Returns true if the given placements are overlapping or they are back-to-back and too far for students.*/
086 public static boolean isInConflict(Placement p1, Placement p2) {
087 return isInConflict(p1, p2, true);
088 }
089
090 public static boolean isInConflict(Placement p1, Placement p2, boolean useDistances) {
091 if (p1==null || p2==null) return false;
092 TimeLocation t1=p1.getTimeLocation(), t2=p2.getTimeLocation();
093 if (!t1.shareDays(t2)) return false;
094 if (!t1.shareWeeks(t2)) return false;
095 if (t1.shareHours(t2)) return true;
096 if (!useDistances) return false;
097 int s1 = t1.getStartSlot(), s2 = t2.getStartSlot();
098 if (s1+t1.getNrSlotsPerMeeting()!=s2 &&
099 s2+t2.getNrSlotsPerMeeting()!=s1) return false;
100 double distance = Placement.getDistance(p1,p2);
101 TimetableModel m = (TimetableModel)p1.variable().getModel();
102 if (m==null) {
103 if (distance <= 67.0) return false;
104 if (distance <= 100.0 && (
105 (t1.getLength()==18 && s1+t1.getLength()==s2) ||
106 (t2.getLength()==18 && s2+t2.getLength()==s1)))
107 return false;
108 return true;
109 } else {
110 if (distance <= m.getStudentDistanceLimit()) return false;
111 if (distance <= m.getStudentDistanceLimit75min() && (
112 (t1.getLength()==18 && s1+t1.getLength()==s2) ||
113 (t2.getLength()==18 && s2+t2.getLength()==s1)))
114 return false;
115 return true;
116 }
117 }
118
119 public void assigned(long iteration, Value value) {
120 super.assigned(iteration, value);
121 if (second()==null || first().getAssignment()==null || second().getAssignment()==null) return;
122 //if (v1.getInitialAssignment()!=null && v2.getInitialAssignment()!=null && v1.getAssignment().equals(v1.getInitialAssignment()) && v2.getAssignment().equals(v2.getInitialAssignment())) return;
123 if (isInConflict((Placement)first().getAssignment(),(Placement)second().getAssignment())) {
124 iAdded=true;
125 ((TimetableModel)getModel()).getViolatedStudentConflictsCounter().inc((long)Math.ceil(iJenrl));
126 if (areStudentConflictsHard())
127 ((TimetableModel)getModel()).getViolatedHardStudentConflictsCounter().inc((long)Math.ceil(iJenrl));
128 if (areStudentConflictsDistance()) {
129 ((TimetableModel)getModel()).getViolatedDistanceStudentConflictsCounter().inc((long)Math.ceil(iJenrl));
130 iAddedDistance = true;
131 }
132 ((Lecture)first()).addActiveJenrl(this);
133 ((Lecture)second()).addActiveJenrl(this);
134 }
135 }
136
137 /** Number of joined enrollments if the given value is assigned to the given variable */
138 public long jenrl(Variable variable, Value value) {
139 Lecture anotherLecture = (Lecture)(first().equals(variable)?second():first());
140 if (anotherLecture.getAssignment()==null) return 0;
141 Lecture lecture = (Lecture) variable;
142 return (isInConflict((Placement)anotherLecture.getAssignment(),(Placement)value)?(long)Math.ceil(iJenrl):0);
143 }
144
145 /** True if the given two lectures overlap in time */
146 public boolean isInConflict() {
147 return iAdded;
148 }
149
150 /** True if the given two lectures overlap in time */
151 public boolean isInConflictPrecise() {
152 return isInConflict((Placement)first().getAssignment(),(Placement)second().getAssignment());
153 }
154
155 /** Increment the number of joined enrollments (during student final sectioning) */
156 public void incJenrl(Student student ) {
157 if (iAdded) {
158 ((TimetableModel)getModel()).getViolatedStudentConflictsCounter().dec((long)Math.ceil(iJenrl));
159 if (areStudentConflictsHard())
160 ((TimetableModel)getModel()).getViolatedHardStudentConflictsCounter().dec((long)Math.ceil(iJenrl));
161 if (iAddedDistance)
162 ((TimetableModel)getModel()).getViolatedDistanceStudentConflictsCounter().dec((long)Math.ceil(iJenrl));
163 }
164 iJenrl+=student.getJenrlWeight((Lecture)first(),(Lecture)second());
165 iNrStrudents++;
166 if (iAdded) {
167 ((TimetableModel)getModel()).getViolatedStudentConflictsCounter().inc((long)Math.ceil(iJenrl));
168 if (areStudentConflictsHard())
169 ((TimetableModel)getModel()).getViolatedHardStudentConflictsCounter().inc((long)Math.ceil(iJenrl));
170 if (iAddedDistance)
171 ((TimetableModel)getModel()).getViolatedDistanceStudentConflictsCounter().inc((long)Math.ceil(iJenrl));
172 }
173 }
174
175 public double getJenrlWeight(Student student) {
176 return student.getJenrlWeight((Lecture)first(),(Lecture)second());
177 }
178
179 /** Decrement the number of joined enrollments (during student final sectioning) */
180 public void decJenrl(Student student) {
181 if (iAdded) {
182 ((TimetableModel)getModel()).getViolatedStudentConflictsCounter().dec((long)Math.ceil(iJenrl));
183 if (areStudentConflictsHard())
184 ((TimetableModel)getModel()).getViolatedHardStudentConflictsCounter().dec((long)Math.ceil(iJenrl));
185 if (iAddedDistance)
186 ((TimetableModel)getModel()).getViolatedDistanceStudentConflictsCounter().dec((long)Math.ceil(iJenrl));
187 }
188 iJenrl-=student.getJenrlWeight((Lecture)first(),(Lecture)second());
189 iNrStrudents--;
190 if (iAdded) {
191 ((TimetableModel)getModel()).getViolatedStudentConflictsCounter().inc((long)Math.ceil(iJenrl));
192 if (areStudentConflictsHard())
193 ((TimetableModel)getModel()).getViolatedHardStudentConflictsCounter().inc((long)Math.ceil(iJenrl));
194 if (iAddedDistance)
195 ((TimetableModel)getModel()).getViolatedDistanceStudentConflictsCounter().inc((long)Math.ceil(iJenrl));
196 }
197 }
198
199 /** Number of joined enrollments (during student final sectioning) */
200 public long getJenrl() { return (long)Math.ceil(iJenrl); }
201 public int getNrStudents() { return iNrStrudents; }
202 public boolean isHard() { return false; }
203
204 public String toString() {
205 return "Joint Enrollment between "+first().getName()+" and "+second().getName();
206 }
207
208 public boolean areStudentConflictsHard() {
209 return ((Lecture)first()).areStudentConflictsHard((Lecture)second());
210 }
211
212 public boolean areStudentConflictsDistance() {
213 return !((Placement)first().getAssignment()).getTimeLocation().hasIntersection(((Placement)second().getAssignment()).getTimeLocation());
214 }
215
216 public boolean areStudentConflictsDistance(Value value) {
217 Placement first = (Placement)(first().equals(value.variable())?value:first().getAssignment());
218 Placement second = (Placement)(second().equals(value.variable())?value:second().getAssignment());
219 if (first==null || second==null) return false;
220 return !first.getTimeLocation().hasIntersection(second.getTimeLocation());
221 }
222
223 public boolean isOfTheSameProblem() {
224 Lecture first = (Lecture)first();
225 Lecture second = (Lecture)second();
226 return ToolBox.equals(first.getSolverGroupId(),second.getSolverGroupId());
227 }
228
229 }