org.cpsolver.studentsct.online.selection

Class OnlineSectioningCriterion

java.lang.Object

org.cpsolver.studentsct.online.selection.OnlineSectioningCriterion

All Implemented Interfaces:

MultiCriteriaBranchAndBoundSelection.SelectionComparator, MultiCriteriaBranchAndBoundSelection.SelectionCriterion

Direct Known Subclasses:

EqualWeightCriterion

public class OnlineSectioningCriterion
extends Object
implements MultiCriteriaBranchAndBoundSelection.SelectionCriterion

Multi-criteria selection criterion. This provides a lexicographical order of solutions using the following criteria:

• best priority & alternativity ignoring free time requests (a better solution has a higher priority course assigned or does not use alternative request if possible)
• avoid or minimize course time overlaps
• minimise use of over-expected classes (this prevents students of getting into classes that we know will be needed later in the process)
• best priority & alternativity including free time requests (this is to prevent students of gaming the system by adding free time requests)
• maximise selection (preferred sections)
• avoid or minimise time overlaps (for classes that are allowed to overlap and for free time requests)
• avoid or minimise distance conflicts
• avoid classes that have no time assignment (arranged hours)
• balance sections
• minimise class penalties (expressing how much a class is over-expected)

Version:

StudentSct 1.3 (Student Sectioning)
Copyright (C) 2014 Tomáš Müller
muller@unitime.org
http://muller.unitime.org

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 3 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 see http://www.gnu.org/licenses.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	OnlineSectioningCriterion.TimeToAvoid Time to be avoided.

Field Summary

Fields

Modifier and Type	Field and Description
protected double[]	iQalityWeights

Constructor Summary

Constructors

Constructor and Description
OnlineSectioningCriterion(Student student, OnlineSectioningModel model, Assignment<Request,Enrollment> assignment, Hashtable<CourseRequest,Set<Section>> preferredSections) Constructor

Method Summary

Modifier and Type	Method and Description
boolean	canImprove(Assignment<Request,Enrollment> assignment, int maxIdx, Enrollment[] current, Enrollment[] best) Bound
int	compare(Assignment<Request,Enrollment> assignment, Enrollment[] current, Enrollment[] best) Compare two solutions
int	compare(Assignment<Request,Enrollment> assignment, Enrollment e1, Enrollment e2) Compare two enrollments
Set<DistanceConflict.Conflict>	getDistanceConflicts(Enrollment[] assignment, int idx) Distance conflicts of idx-th assignment of the current schedule
protected OnlineSectioningModel	getModel()
protected Set<Section>	getPreferredSections(Request request)
Request	getRequest(int index)
protected Student	getStudent()
Set<StudentQuality.Conflict>	getStudentQualityConflicts(Enrollment[] assignment, int idx)
Set<TimeOverlapsCounter.Conflict>	getTimeOverlappingConflicts(Enrollment[] assignment, int idx) Time overlapping conflicts of idx-th assignment of the current schedule
protected List<OnlineSectioningCriterion.TimeToAvoid>	getTimesToAvoid()
double	getTotalWeight(Assignment<Request,Enrollment> assignment, Enrollment[] enrollemnts) For backward compatibility, return a weighted sum
protected double	getWeight(Assignment<Request,Enrollment> assignment, Enrollment enrollment, Set<DistanceConflict.Conflict> distanceConflicts, Set<TimeOverlapsCounter.Conflict> timeOverlappingConflicts) Deprecated.
protected double	getWeight(Assignment<Request,Enrollment> assignment, Enrollment enrollment, Set<StudentQuality.Conflict> conflicts)
boolean	isFreeTime(int index)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

iQalityWeights

protected double[] iQalityWeights

Constructor Detail

OnlineSectioningCriterion

public OnlineSectioningCriterion(Student student,
                                 OnlineSectioningModel model,
                                 Assignment<Request,Enrollment> assignment,
                                 Hashtable<CourseRequest,Set<Section>> preferredSections)

Constructor

Parameters:

student - current student

model - online student sectioning model

assignment - current assignment

preferredSections - preferred sections

Method Detail

getModel

protected OnlineSectioningModel getModel()

getStudent

protected Student getStudent()

getPreferredSections

protected Set<Section> getPreferredSections(Request request)

getTimesToAvoid

protected List<OnlineSectioningCriterion.TimeToAvoid> getTimesToAvoid()

getDistanceConflicts

public Set<DistanceConflict.Conflict> getDistanceConflicts(Enrollment[] assignment,
                                                           int idx)

Distance conflicts of idx-th assignment of the current schedule

getTimeOverlappingConflicts

public Set<TimeOverlapsCounter.Conflict> getTimeOverlappingConflicts(Enrollment[] assignment,
                                                                     int idx)

Time overlapping conflicts of idx-th assignment of the current schedule

getStudentQualityConflicts

public Set<StudentQuality.Conflict> getStudentQualityConflicts(Enrollment[] assignment,
                                                               int idx)

getWeight

@Deprecated
protected double getWeight(Assignment<Request,Enrollment> assignment,
                                       Enrollment enrollment,
                                       Set<DistanceConflict.Conflict> distanceConflicts,
                                       Set<TimeOverlapsCounter.Conflict> timeOverlappingConflicts)

Deprecated.

Weight of an assignment. Unlike StudentWeights.getWeight(Assignment, Enrollment, Set, Set), only count this side of distance conflicts and time overlaps.

getWeight

protected double getWeight(Assignment<Request,Enrollment> assignment,
                           Enrollment enrollment,
                           Set<StudentQuality.Conflict> conflicts)

getRequest

public Request getRequest(int index)

isFreeTime

public boolean isFreeTime(int index)

compare

public int compare(Assignment<Request,Enrollment> assignment,
                   Enrollment[] current,
                   Enrollment[] best)

Description copied from interface: MultiCriteriaBranchAndBoundSelection.SelectionCriterion

Compare two solutions

Specified by:

compare in interface MultiCriteriaBranchAndBoundSelection.SelectionCriterion

Parameters:

assignment - current assignment

current - current solution

best - best known solution

Returns:

true if current solution is better than the best one

canImprove

public boolean canImprove(Assignment<Request,Enrollment> assignment,
                          int maxIdx,
                          Enrollment[] current,
                          Enrollment[] best)

Description copied from interface: MultiCriteriaBranchAndBoundSelection.SelectionCriterion

Bound

Specified by:

canImprove in interface MultiCriteriaBranchAndBoundSelection.SelectionCriterion

Parameters:

assignment - current assignment

maxIdx - current request index

current - current solution

best - best known solution

Returns:

if the current solution can be extended and possibly improve upon the best known solution

getTotalWeight

public double getTotalWeight(Assignment<Request,Enrollment> assignment,
                             Enrollment[] enrollemnts)

Description copied from interface: MultiCriteriaBranchAndBoundSelection.SelectionCriterion

For backward compatibility, return a weighted sum

Specified by:

getTotalWeight in interface MultiCriteriaBranchAndBoundSelection.SelectionCriterion

Parameters:

assignment - current assignment

enrollemnts - current solution

Returns:

solution weight (weighted sum)

compare

public int compare(Assignment<Request,Enrollment> assignment,
                   Enrollment e1,
                   Enrollment e2)

Description copied from interface: MultiCriteriaBranchAndBoundSelection.SelectionComparator

Compare two enrollments

Specified by:

compare in interface MultiCriteriaBranchAndBoundSelection.SelectionComparator

Parameters:

assignment - current assignment

e1 - first enrollment

e2 - second enrollment

Returns:

-1 if the first enrollment is better than the second etc.