net.sf.cpsolver.exam.model
Class ExamPlacement

java.lang.Object
  net.sf.cpsolver.ifs.model.Value
      net.sf.cpsolver.exam.model.ExamPlacement

All Implemented Interfaces:

Comparable

public class ExamPlacement
extends Value

Representation of an exam placement (problem value), i.e., assignment of an exam to period and room(s). Each placement has defined a period and a set of rooms. The exam as well as the rooms have to be available during the given period (see Exam.getPeriodPlacements() and Exam.getRoomPlacements()). The total size of rooms have to be equal or greater than the number of students enrolled in the exam Exam.getSize(), using either ExamRoom.getSize() or ExamRoom.getAltSize(), depending on Exam.hasAltSeating(). Also, the number of rooms has to be smaller or equal to Exam.getMaxRooms(). If Exam.getMaxRooms() is zero, the exam is only to be assigned to period (the set of rooms is empty).

The cost of an assignment consists of the following criteria:

• Direct student conflicts getNrDirectConflicts(), weighted by ExamModel.getDirectConflictWeight()
• More than two exams a day student conflicts getNrMoreThanTwoADayConflicts(), weighted by ExamModel.getMoreThanTwoADayWeight()
• Back-to-back student conflicts getNrBackToBackConflicts(), weighted by ExamModel.getBackToBackConflictWeight()
• Distance back-to-back student conflicts getNrDistanceBackToBackConflicts(), weighted by ExamModel.getDistanceBackToBackConflictWeight()
• Period penalty getPeriodPenalty(), weighted by ExamModel.getPeriodWeight()
• Room size penalty getRoomSizePenalty(), weighted by ExamModel.getRoomSizeWeight()
• Room split penalty getRoomSplitPenalty(), weighted by ExamModel.getRoomSplitWeight()
• Room penalty getRoomPenalty(), weighted by ExamModel.getRoomWeight()
• Exam rotation penalty getRotationPenalty(), weighted by ExamModel.getExamRotationWeight()
• Direct instructor conflicts getNrInstructorDirectConflicts(), weighted by ExamModel.getInstructorDirectConflictWeight()
• More than two exams a day instructor conflicts getNrInstructorMoreThanTwoADayConflicts(), weighted by ExamModel.getInstructorMoreThanTwoADayWeight()
• Back-to-back instructor conflicts getNrInstructorBackToBackConflicts(), weighted by ExamModel.getInstructorBackToBackConflictWeight()
• Distance back-to-back instructor conflicts getNrInstructorDistanceBackToBackConflicts(), weighted by ExamModel.getInstructorDistanceBackToBackConflictWeight()

Version:

ExamTT 1.1 (Examination Timetabling)
Copyright (C) 2008 Tomáš Müller
muller@unitime.org
Lazenska 391, 76314 Zlin, Czech Republic

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

Field Summary

Fields inherited from class net.sf.cpsolver.ifs.model.Value

iValue

Constructor Summary

ExamPlacement(Exam exam, ExamPeriodPlacement periodPlacement, Set roomPlacements)
Constructor

Method Summary

boolean	contains(ExamRoom room) True if given room is between getRoomPlacements()
boolean	equals(Object o) Compare two assignments for equality
int	getDistance(ExamPlacement other) Distance between two placements, i.e., maximal distance between a room of this placement and a room of the given placement.
double	getDistributionPenalty() Distribution penalty, i.e., sum weights of violated distribution constraints
int	getLargePenalty() Front load penalty (large exam is discouraged to be placed on or after a certain period)
String	getName() Assignment name (period / room(s))
int	getNrBackToBackConflicts() Number of back-to-back student conflicts, i.e., number of cases when this exam is attended by a student that attends some other exam at the previous ExamPeriod.prev() or following ExamPeriod.next() period.
int	getNrDirectConflicts() Number of direct student conflicts, i.e., number of cases when this exam is attended by a student that attends some other exam at the same period
int	getNrDistanceBackToBackConflicts() Number of back-to-back distance student conflicts, i.e., number of cases when this exam is attended by a student that attends some other exam at the previous ExamPeriod.prev() or following ExamPeriod.next() period and the distance getDistance(ExamPlacement) between these two exams is greater than ExamModel.getBackToBackDistance().
int	getNrInstructorBackToBackConflicts() Number of back-to-back instructor conflicts, i.e., number of cases when this exam is attended by an instructor that attends some other exam at the previous ExamPeriod.prev() or following ExamPeriod.next() period.
int	getNrInstructorDirectConflicts() Number of direct instructor conflicts, i.e., number of cases when this exam is attended by an instructor that attends some other exam at the same period
int	getNrInstructorDistanceBackToBackConflicts() Number of back-to-back distance instructor conflicts, i.e., number of cases when this exam is attended by an instructor that attends some other exam at the previous ExamPeriod.prev() or following ExamPeriod.next() period and the distance getDistance(ExamPlacement) between these two exams is greater than ExamModel.getBackToBackDistance().
int	getNrInstructorMoreThanTwoADayConflicts() Number of more than two exams a day instructor conflicts, i.e., when this exam is attended by an instructor student that attends two or more other exams at the same day.
int	getNrInstructorNotAvailableConflicts() Number of direct instructor conflicts caused by the fact that a student is not available
int	getNrMoreThanTwoADayConflicts() Number of more than two exams a day student conflicts, i.e., when this exam is attended by a student that attends two or more other exams at the same day.
int	getNrNotAvailableConflicts() Number of direct student conflicts caused by the fact that a student is not available
ExamPeriod	getPeriod() Assigned period
double	getPeriodDistributionPenalty() Period related distribution penalty, i.e., sum weights of violated distribution constraints
int	getPeriodPenalty() Cost for using a period, i.e., ExamPeriodPlacement.getPenalty()
ExamPeriodPlacement	getPeriodPlacement() Assigned period placement
int	getPerturbationPenalty() Perturbation penalty, i.e., penalty for using a different assignment than initial.
double	getRoomCost() Overall cost of using this set or rooms.
double	getRoomDistributionPenalty() Room related distribution penalty, i.e., sum weights of violated distribution constraints
String	getRoomName(String delim) Room names separated with the given delimiter
int	getRoomPenalty() Room penalty (penalty for using given rooms), i.e., sum of ExamRoomPlacement.getPenalty(ExamPeriod) of assigned rooms
int	getRoomPerturbationPenalty() Room perturbation penalty, i.e., number of assigned rooms different from initial.
Set	getRoomPlacements() Assigned rooms (it is empty when Exam.getMaxRooms() is zero)
int	getRoomSizePenalty() Cost for using room(s) that are too big
double	getRoomSplitDistancePenalty() Room split distance penalty, i.e., average distance between two rooms of this placement
int	getRoomSplitPenalty() Cost for using more than one room (nrSplits^2).
int	getRotationPenalty() Rotation penalty (an exam that has been in later period last times tries to be in an earlier period)
int	getSize() Overall size of assigned rooms
double	getTimeCost() Overall cost of using this period.
int	hashCode() Hash code
double	toDouble() Overall cost of using this placement.
String	toString() String representation -- returns a list of assignment costs

Methods inherited from class net.sf.cpsolver.ifs.model.Value

assigned, compareTo, conflicts, countAssignments, getDescription, getExtra, getId, isConsistent, lastAssignmentIteration, lastUnassignmentIteration, setExtra, setVariable, unassigned, valueEquals, variable

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ExamPlacement

public ExamPlacement(Exam exam,
                     ExamPeriodPlacement periodPlacement,
                     Set roomPlacements)

Constructor

Parameters:

exam - an exam

periodPlacement - period placement

roomPlacements - a set of room placements ExamRoomPlacement

Method Detail

getPeriod

public ExamPeriod getPeriod()

Assigned period

getPeriodPlacement

public ExamPeriodPlacement getPeriodPlacement()

Assigned period placement

getRoomPlacements

public Set getRoomPlacements()

Assigned rooms (it is empty when Exam.getMaxRooms() is zero)

Returns:

list of ExamRoomPlacement

getSize

public int getSize()

Overall size of assigned rooms

getNrDirectConflicts

public int getNrDirectConflicts()

Number of direct student conflicts, i.e., number of cases when this exam is attended by a student that attends some other exam at the same period

getNrNotAvailableConflicts

public int getNrNotAvailableConflicts()

Number of direct student conflicts caused by the fact that a student is not available

getNrBackToBackConflicts

public int getNrBackToBackConflicts()

Number of back-to-back student conflicts, i.e., number of cases when this exam is attended by a student that attends some other exam at the previous ExamPeriod.prev() or following ExamPeriod.next() period. If ExamModel.isDayBreakBackToBack() is false, back-to-back conflicts are only considered between consecutive periods that are of the same day.

getDistance

public int getDistance(ExamPlacement other)

Distance between two placements, i.e., maximal distance between a room of this placement and a room of the given placement. Method ExamRoom.getDistance(ExamRoom) is used to get a distance between two rooms.

getNrDistanceBackToBackConflicts

public int getNrDistanceBackToBackConflicts()

Number of back-to-back distance student conflicts, i.e., number of cases when this exam is attended by a student that attends some other exam at the previous ExamPeriod.prev() or following ExamPeriod.next() period and the distance getDistance(ExamPlacement) between these two exams is greater than ExamModel.getBackToBackDistance(). Distance back-to-back conflicts are only considered between consecutive periods that are of the same day.

getNrMoreThanTwoADayConflicts

public int getNrMoreThanTwoADayConflicts()

Number of more than two exams a day student conflicts, i.e., when this exam is attended by a student that attends two or more other exams at the same day.

getNrInstructorDirectConflicts

public int getNrInstructorDirectConflicts()

Number of direct instructor conflicts, i.e., number of cases when this exam is attended by an instructor that attends some other exam at the same period

getNrInstructorNotAvailableConflicts

public int getNrInstructorNotAvailableConflicts()

Number of direct instructor conflicts caused by the fact that a student is not available

getNrInstructorBackToBackConflicts

public int getNrInstructorBackToBackConflicts()

Number of back-to-back instructor conflicts, i.e., number of cases when this exam is attended by an instructor that attends some other exam at the previous ExamPeriod.prev() or following ExamPeriod.next() period. If ExamModel.isDayBreakBackToBack() is false, back-to-back conflicts are only considered between consecutive periods that are of the same day.

getNrInstructorDistanceBackToBackConflicts

public int getNrInstructorDistanceBackToBackConflicts()

Number of back-to-back distance instructor conflicts, i.e., number of cases when this exam is attended by an instructor that attends some other exam at the previous ExamPeriod.prev() or following ExamPeriod.next() period and the distance getDistance(ExamPlacement) between these two exams is greater than ExamModel.getBackToBackDistance(). Distance back-to-back conflicts are only considered between consecutive periods that are of the same day.

getNrInstructorMoreThanTwoADayConflicts

public int getNrInstructorMoreThanTwoADayConflicts()

Number of more than two exams a day instructor conflicts, i.e., when this exam is attended by an instructor student that attends two or more other exams at the same day.

getRoomSizePenalty

public int getRoomSizePenalty()

Cost for using room(s) that are too big

Returns:

difference between total room size (computed using either ExamRoom.getSize() or ExamRoom.getAltSize() based on Exam.hasAltSeating()) and the number of students Exam.getSize()

getRoomSplitPenalty

public int getRoomSplitPenalty()

Cost for using more than one room (nrSplits^2).

Returns:

penalty (1 for 2 rooms, 4 for 3 rooms, 9 for 4 rooms, etc.)

getPeriodPenalty

public int getPeriodPenalty()

Cost for using a period, i.e., ExamPeriodPlacement.getPenalty()

getRotationPenalty

public int getRotationPenalty()

Rotation penalty (an exam that has been in later period last times tries to be in an earlier period)

getLargePenalty

public int getLargePenalty()

Front load penalty (large exam is discouraged to be placed on or after a certain period)

Returns:

zero if not large exam or if before ExamModel.getLargePeriod(), one otherwise

getRoomPenalty

public int getRoomPenalty()

Room penalty (penalty for using given rooms), i.e., sum of ExamRoomPlacement.getPenalty(ExamPeriod) of assigned rooms

getPerturbationPenalty

public int getPerturbationPenalty()

Perturbation penalty, i.e., penalty for using a different assignment than initial. Only applicable when ExamModel.isMPP() is true (minimal perturbation problem).

Returns:

|period index - initial period index | * exam size

getRoomPerturbationPenalty

public int getRoomPerturbationPenalty()

Room perturbation penalty, i.e., number of assigned rooms different from initial. Only applicable when ExamModel.isMPP() is true (minimal perturbation problem).

Returns:

|period index - initial period index | * exam size

getRoomSplitDistancePenalty

public double getRoomSplitDistancePenalty()

Room split distance penalty, i.e., average distance between two rooms of this placement

getDistributionPenalty

public double getDistributionPenalty()

Distribution penalty, i.e., sum weights of violated distribution constraints

getRoomDistributionPenalty

public double getRoomDistributionPenalty()

Room related distribution penalty, i.e., sum weights of violated distribution constraints

getPeriodDistributionPenalty

public double getPeriodDistributionPenalty()

Period related distribution penalty, i.e., sum weights of violated distribution constraints

toDouble

public double toDouble()

Overall cost of using this placement. The cost of an assignment consists of the following criteria:

• Direct student conflicts getNrDirectConflicts(), weighted by ExamModel.getDirectConflictWeight()
• More than two exams a day student conflicts getNrMoreThanTwoADayConflicts(), weighted by ExamModel.getMoreThanTwoADayWeight()
• Back-to-back student conflicts getNrBackToBackConflicts(), weighted by ExamModel.getBackToBackConflictWeight()
• Distance back-to-back student conflicts getNrDistanceBackToBackConflicts(), weighted by ExamModel.getDistanceBackToBackConflictWeight()
• Period penalty getPeriodPenalty(), weighted by ExamModel.getPeriodWeight()
• Room size penalty getRoomSizePenalty(), weighted by ExamModel.getRoomSizeWeight()
• Room split penalty getRoomSplitPenalty(), weighted by ExamModel.getRoomSplitWeight()
• Room split distance penalty getRoomSplitDistancePenalty(), weighted by ExamModel.getRoomSplitDistanceWeight()
• Room penalty getRoomPenalty(), weighted by ExamModel.getRoomWeight()
• Exam rotation penalty getRotationPenalty(), weighted by ExamModel.getExamRotationWeight()
• Direct instructor conflicts getNrInstructorDirectConflicts(), weighted by ExamModel.getInstructorDirectConflictWeight()
• More than two exams a day instructor conflicts getNrInstructorMoreThanTwoADayConflicts(), weighted by ExamModel.getInstructorMoreThanTwoADayWeight()
• Back-to-back instructor conflicts getNrInstructorBackToBackConflicts(), weighted by ExamModel.getInstructorBackToBackConflictWeight()
• Distance back-to-back instructor conflicts getNrInstructorDistanceBackToBackConflicts(), weighted by ExamModel.getInstructorDistanceBackToBackConflictWeight()
• Front load penalty getLargePenalty(), weighted by ExamModel.getLargeWeight()

Overrides:

toDouble in class Value

getTimeCost

public double getTimeCost()

Overall cost of using this period. The time cost of an assignment consists of the following criteria:

• Direct student conflicts getNrDirectConflicts(), weighted by ExamModel.getDirectConflictWeight()
• More than two exams a day student conflicts getNrMoreThanTwoADayConflicts(), weighted by ExamModel.getMoreThanTwoADayWeight()
• Back-to-back student conflicts getNrBackToBackConflicts(), weighted by ExamModel.getBackToBackConflictWeight()
• Period penalty getPeriodPenalty(), weighted by ExamModel.getPeriodWeight()
• Exam rotation penalty getRotationPenalty(), weighted by ExamModel.getExamRotationWeight()
• Direct instructor conflicts getNrInstructorDirectConflicts(), weighted by ExamModel.getInstructorDirectConflictWeight()
• More than two exams a day instructor conflicts getNrInstructorMoreThanTwoADayConflicts(), weighted by ExamModel.getInstructorMoreThanTwoADayWeight()
• Back-to-back instructor conflicts getNrInstructorBackToBackConflicts(), weighted by ExamModel.getInstructorBackToBackConflictWeight()
• Distance back-to-back instructor conflicts getNrInstructorDistanceBackToBackConflicts(), weighted by ExamModel.getInstructorDistanceBackToBackConflictWeight()
• Front load penalty getLargePenalty(), weighted by ExamModel.getLargeWeight()

getRoomCost

public double getRoomCost()

Overall cost of using this set or rooms. The room cost of an assignment consists of the following criteria:

• Distance back-to-back student conflicts getNrDistanceBackToBackConflicts(), weighted by ExamModel.getDistanceBackToBackConflictWeight()
• Distance back-to-back instructor conflicts getNrInstructorDistanceBackToBackConflicts(), weighted by ExamModel.getInstructorDistanceBackToBackConflictWeight()
• Room size penalty getRoomSizePenalty(), weighted by ExamModel.getRoomSizeWeight()
• Room split penalty getRoomSplitPenalty(), weighted by ExamModel.getRoomSplitWeight()
• Room split distance penalty getRoomSplitDistancePenalty(), weighted by ExamModel.getRoomSplitDistanceWeight()
• Room penalty getRoomPenalty(), weighted by ExamModel.getRoomWeight()

getRoomName

public String getRoomName(String delim)

Room names separated with the given delimiter

getName

public String getName()

Assignment name (period / room(s))

Overrides:

getName in class Value

toString

public String toString()

String representation -- returns a list of assignment costs

Overrides:

toString in class Value

equals

public boolean equals(Object o)

Compare two assignments for equality

Overrides:

equals in class Value

hashCode

public int hashCode()

Hash code

Overrides:

hashCode in class Value

contains

public boolean contains(ExamRoom room)

True if given room is between getRoomPlacements()