Student exam constrain

[Animeakihabara]

Is there any way to limit the max student can have exam per day or max student can have exam per exam period?

[tomas-muller]

It is currently not possible to limit the number of students who will have exams during a particular period or on a particular day.

The constraints are per student, namely:

• prohibiting or minimizing the number of direct conflicts (a student has two exams in the same period)
• minimizing more than two exams on a day (a student has three or more exams on a particular day)
  • optionally, there is a variant minimizing two or more exams on a day
• minimizing back-to-back conflicts (a student has two exams in consecutive periods)
  • possibility also considering travel times (distance back-to-back conflicts when the travel time exceeds a given threshold)

[Animeakihabara]

how can i setting up these constraints, about the name, the value, ... of these constraints in unitime?

[tomas-muller]

The direct student conflicts, more than two exams on a day student conflicts, and back-to-back (distance) student conflicts are configured automatically. You can modify the solver weights for a particular solver configuration on the Administration > Solver > Configuration page. Together with the weights on the periods, rooms, and soft distribution preferences.

[Animeakihabara]

That mean, when i want minimizing more than two exams on a day I just need increase the value higher than the value of others constraints

[tomas-muller]

The objective function the solver tries to minimize is a weighted sum of the various criteria. So, yes, putting a higher weight on a particular criterion (such as more than two exams on a day student conflicts) will make the solver concentrate on the criterion more.

[shaftain]

I have question related to this discussion, @tomas-muller, you mentioned in your reply:

• optionally, there is a variant minimizing two or more exams on a day

How to enable this option? Is there any Property that needs to be entered in Application Settings?

[tomas-muller]

The more than one examination on a day is implemented as an additional criterion StudentMoreThan1ADayConflicts. The class name needs to be added to the additional criteria for the solver (which contains a semicolon-separated list of additional criteria that are to be used).

This can be done on the Administration > Solver > Parameters page, select Examinations: General Parameters, and edit the Exams.AdditionalCriteria parameter so that it contains

org.cpsolver.exam.criteria.additional.DistanceToStronglyPreferredRoom;org.cpsolver.exam.criteria.additional.StudentMoreThan1ADayConflicts

as the default value (or just the org.cpsolver.exam.criteria.additional.StudentMoreThan1ADayConflicts).