Hey,
I have 150 parents, 10 teachers, and the parents can pick three to five teachers to speak with. Slots are about 8 minutes and we have about 20 slots per evening. Locations are irrelevant, since we will organize these in our school canteen anyway.
I've been to Craiova to visit Netrom, btw. Great city!
Can these parent-teacher conferences be organized using FET?
Slinger
I am not sure I understood completely your requirements. I suppose that you need each parent to talk to each teacher, in conferences that have a parent and 3-5 teachers. Please correct me if I am wrong.
It might be possible to use some tricks, like:
Consider each real parent -> A FET ROOM.
Each real teacher -> A FET TEACHER.
Then, you have some ACTIVITIES, each one with its TEACHER. Each activity will have the number of students = 1 (this is inputted by you).
You need to put these ACTIVITIES into ROOMS, so that each ROOM has at most 5 activities at the same time and at least 3.
So, add n real parents -> ROOMS, with capacity 5.
Add n real parents -> SUBJECTS.
Add n real teachers -> TEACHERS.
Add n real teachers * n real parents -> ACTIVITIES, each with a single teacher, each with a SUBJECT which represents a real parent. So, if you have 2 teachers and 3 parents, add 6 activities: A1(teacher=t1, subject=s1, students set=none), A2(t1, s2), A3(t1, s3), A4(t2, s1), A5(t2, s2), A6(t2, s3).
Add n real parents number of constraints subject preferred room, for each parent preferred ROOM the corresponding ROOM (say, you have SUBJECTS s1, s2, ..., sn and ROOMS r1, r2, ..., rn).
Now, when FET schedules, it puts at most 5 activities in each ROOM. The minimum 3 activities in each ROOM is not taken care of - is this a problem?
Please let me know your opinion.
This is looking great: I would get the resulting schedule for 1 evening without problems, right? When I said 3-5 appointments I actually meant 0-5 appointments, so that's great.
How would the algorithm perform, btw, for about 150 parents and 20 teachers? And does FET come with APT-Get for Ubuntu?
Could you please put some of those example scripts up?
Slinger
I saw now that you wrote you visited Craiova :-)
For 150 parents and 10 teachers you have 10*150=1500 activities. But it is a simple timetable for FET, might be under 1 minute to generate.
I don't know about Ubuntu. They have some package, I am not sure if you have it by default and it might be (very) old. I recommend to compile latest 5.8.0.
What do you mean by those example scripts up?
Please try a small data file before you embark on writing the whole data. I might have misunderstood your requirements and I don't want to waste your time. So maybe read again what I wrote above.
I'll do now a small program to generate a .fet data file for you, with 150 SUBJECTS/ROOMS and 10 TEACHERS, and will let you know, maybe attach the file here. This is easy for me to do and I am curious about the result.
Please note: the maximum number of activities in FET is 5000. If you need more, you have to modify the sources.
Sorry, I did a mistake, each room can keep only one activity at a moment in time. So, it is needed to add 5 rooms for each real parent. The solution might be still possible, I am working on it.
Also, I think I misunderstood that you have 150 parents and each one of them must consult 3-5 teachers. I think you want to split these 150 parents into groups of say 10, and 10 parents meet at once with 3-5 teachers, is that correct? Are these groups of parents the same all the time?
Later edit: please describe the situation more detailed, I did not understand completely
Oh no, you are reading too much into it. It's a simple problem, and your previous solution sounds just right. Each parent will want a single meeting with a teacher to discuss report grades. Generally, there will be teachers who are overbooked (getting more requests than there are slots in the evening), but we will simply draw a cut-off point for those teachers who are overbooked at the amount of slots on a given evening.
So the idea is that a parent comes in at the planned time, has one to five (consecutive or almost consecutive with some holes in his/her schedule) meetings with separate teachers sitting at separate tables. Then the parent goes home again, hopefully feeling well informed about their children and their performance in school.
5000 events is a limit I am willing to accept, btw. I currently have a max of 150 parents having a max of 5 meetings, which adds up to 750. Should there be more than 5000, I'll drop you an e-mail to ask about where I can change this in the source code or config files :-).
Finally, 1-5 minutes sounds amazing. We used to use Tablix, but that takes anywhere between 30 minutes and 2 days. Sometimes without a solution!
Thanks for your exemplary handling of this! I have been treated well at forums before, but this is amazing.
Slinger
Then I think we should make parents=FET students, teacher=FET teachers.
But there is something I don't understand: each teacher can have maximum 20 free periods per day (20 periods of 8 minutes). So, FET cannot find a solution, because the teachers don't have enough time.
Also, you cannot have overbooked teachers in FET.
Nope, that was my point. We will cut it off (at 20), before we feed the scheduler an impossible problem.
So you can have a maximum of 10 teachers x 20 periods = 200 activities, from a total of 10 teachers x 150 parents = 1500. How can you choose these activities? Aren't these 200 too little? Do you mean to use the whole week or only one day?
You can tell FET that a parent must have say 4 meetings with at most 2 gaps by adding a constraint students max 2 gaps per week, so this can be solved.
I can tell you that in the past, FET used a similar algorithm with Tablix and was very slow and didn't find a solution, but I added a new one and now the things are all right, it solves like commercial tools, very fast.
Great to hear about the comparison to commercial tools! Good job.
you assertions are right, there are 200 activities max, but generally, many parents do not apply for their 5 slots. Often they will not come. The cut-off point is generally through fairness, so if a parent has two overbooked teachers, the parent will get at least one of them. It's fairly simple, really.
The amount of gaps is not so important, btw. As long as the day is planned and the parent does not have to come by from 17:00-22:00 for three five minute meetings.
If FET solves my problems, btw, I will definitely get my boss to donate :-).
Slinger
I have made a random generator (random 200 activities from a total possible of 1500). It seems to work, I even added max 2 gaps for parents and solves in a few seconds. I attach the .cpp file (you need to compile to generate) and a sample input file, which you can open with FET and solve.
Please let me know what you think.
Thank you for the kind thought!
You can also try with less gaps (zero works OK).
If you can solve your input file with official FET, I would like to move this topic to the FET Support - Get Help - may I?