Scheduling Student Sets in US High School - Issue

[Scott Miller]

We are trying to use FET to schedule students into a typical American High School schedule.

We decided to start simple and only schedule student sets.  Each student is its own set.  We did not attempt to schedule teachers or rooms yet.

In order to assign student sets to an Activity, we 1st determined the total number of Activities needed to schedule all students requesting the subject, and then we randomly
assigned the student sets to each of the Activities based on how many students we wanted in the activity. This was done before loading Activities into FET.

We have a total of 138 unique teaching activities split into 690 activities (All activities meet 5 days, MTWRF). All activities meet 1 period each day.

We expected to be able to schedule 690 activities in a timetable of 10 periods a day, 5 days a week.

We only have two Activity Time Constraints:

     1.   A set of activities has the same starting hour (95%)
     2.   Minimum days between a set of activities (100%)

Using 10 periods a day, we get maybe 30% of the students scheduled (200+ activities), and the program seems to go into a loop. We even left it schedule over night for 15 hours,
and it never finished.

However, if we simply add 2 more periods a day (12 periods a day, just for testing purposes), all 690 activities are scheduled in under
5 minutes.

We are hoping FET can be the solution to our scheduling needs.  I have uploaded a file to see if you have any ideas what might be going wrong?

[Liviu Lalescu]

1) You mean min days with 95% and same starting hour with 100%, isn't it? (reverse from what you wrote.)

2) I am not sure I understand why you added same starting hour constraints like that. The timetable is identical each day? You may just schedule a single day, in this case, because FET will be faster and data simpler for the human user.

3) When generating on your original file, it gets stuck at 200 activities. Problematic activity id: 61. I interrupted generation and saw the students' timetable. There is no directly available slot for this activity. Edited to add: The sentence "There is no directly available slot for this activity" does not mean that the timetable is impossible. FET can do recursive swaps to make space for the next activities to be placed. The sentence means just that it is possible to see the partial timetable and have an idea over the timetable data.

4) I removed all your time constraints (Edited to add: Without the basic constraints, of course). FET went to 280 activities, I interrupted it, and the problematic activity id was 396.

Knowing that there are many successful FET users, I really think your data is too constrained (I refer to the basic time constraints for students). I think you need to redesign the allocation of students to activities.

If you want to assign activities to students, you may do that in FET, using a trick: a real student = a FET room.

Please let me know.