Problems with subgroups

[scm060]

Hi

I have used FET for smaller projects until now. I have now a new task to build a timetable for a chamber music course.

• 6 teachers
• 37 students
• 2 days (in fact, there are 6 days, but there are two "model days" (A+B), repeated two times)
• 7 Hours a day
• Some room restrictions, but these data are not yet available
• Students play in groups between 2 and 9 persons, each group can play only 1 time a day
• Some groups play only on 1 day, others on two days (days A+B)
• A group is teached by 1 teacher (always the same)

I used the example 3: High School and Universitäres and added the data accordingly (imported csv-file). As Most of the students play in several group, there are several identical subgroups (as subgroup = student). When I have only 8 groups, it works perfectly. But when I add more groups, the timetable can not be generated: "... because the number of hours for subgroup is 16 and you have only 2 days x 7 hours in a week. But I have 6 teachers x 2 days x 7 hours = 84 possibilities.

What I am doing wrong here?  (FET-file attached)

Thanks
M

[Liviu Lalescu]

Hello,

I attach the corrected file. I removed the year 2019 from each activity, and added a comment on a useless constraint and made the weight of min days between activities 100% instead of 95%. I hope this is what you need.

Explanation: each activity with the year 2019 considers that it has all the subgroups (students) of this year.

PS: The students' year can be named in any way, not necessarily the real year of the today's date.

PPS: What means "the example 3: High School and Universitäres"?

[scm060]

Hi Liviu

Perfect, thanks!
PPS: "Example 3: High School and Universities" in the FET-Manual

Best
Markus

[scm060]

Hi
I have expanded this one:
- each activity is splitted, added tags * (without teacher), + (with teacher). Most of the groups have one without, one with teacher; only a few one have both sessions with the same teacher.
- More timeslots (additional times for sessions without teacher)
- Added a Time constraint 100% for all sessions with teacher (activity tag +) to omit sessions with teacher in the additional timeslots > in the timeslots marked yellow in the pdf, there should be no activities with teacher, only without teacher (activity tag *).

The system finds solutions and says "number of broken soft constraints: 0", but there are some activities with teachers in these additional timeslots. Any clue, what I should change here?

And by the way: do you have a Donation system?

Best M

[Liviu Lalescu]

I think this is what you need (attached). You added only the 1st subactivity - this will neglect the 2nd subactivity from an activity split into 2 with a teacher in both components. I deactivated this constraint and added a correct one.

Thank you for your kind intention! There is a donation page on the main FET homepage, in the menu on the left.

[scm060]

Thanks a lot. So, I have to add this constraint to activity and not to subactivity, is this correct?
Works as a charm!

M

[Liviu Lalescu]

Either to all activities, or to subactivities with component 1 and subactivities with component 2, if you only have activities divided into 2, but this is more work. Subactivities with component 1 mean the first division of an activity, and so on. For instance, if large split activity has ids 4, 5, 6 (split into 3), the subactivity with component 1 is id 4, component 2 is id 5, and component 3 is id 6.

You are welcome!