I have been reading pdf files, watching videos, and looking for some answers on the Forum... but I can not find how to solve whatever the issue is that I am having (I can not even understand what might be the problem with my current timetable). I have been running the program several times, but it does not deliver any final timetable. How can I find someone to help me out, a donation to the creator(s) of FET was already on mind, but I have not been successful in creating a final timetable (or timetables if possible). HELP! THANKS!
One thing that could be part of the problem, is that I might have some problems with activities that are scheduled the same day, but there might be a constraint (or a lack of it) that does not allow for the system to consider the option of putting them together. The first time I ran the program, I was able to learn that I was creating the activities incorrectly (I was not giving them splits, so they had to be continuous/together/next to each other/immediately after the other). I made the correction, and when creating the activities, I created a split for them (if the class is of 2 hours, 2 splits. 3 hours, 3 splits. etc.) and I left the option of "if a same activity appears more than once in the same day, put it together" marked, but that seemed to be a mandatory constraint instead of an optional one. Finally what I did was I left the option unmarked, but that seems to be a mandatory constraint that if they are on the same day, they can´t be together OR that they can not be on the same day?
This journey has been amazing so far, but it is not over, and time is running out. Thanks again!
Hello,
I will try to help as soon as possible. Thank you very much for the thought of sustaining this project financially, which is desperately needed!
If you don't select "consecutive if same day", they can be on the same day consecutive or not, or on different days.
Please wait for me to check the problems and I will let you know immediately when possible. On thing I noticed, it blocks at 147/176, which is usually a bug in the input data.
Hello,
I deactivated the constraint teacher not available (available only on Friday) for Frederic Lefebvre, and the timetable is possible. I attach liviub.fet.
Then I tried to make for this teacher only 1 working day, but it is impossible.
Then I made for this teacher 2 working days, and it is possible (attached liviub3.fet).
Your initial file is probably too constrained. If you really need the original constraint, we need to try something else. But having this teacher available only on one day seems like an input mistake for me.
Than you very much for your fast answer Liviu! I did notice it was stuck on 147, and from what I understood, I had to check k+1 (148). I checked 147 and 148, but either I don´t find or I don´t understand what the problem would be. Again, amazing software, I have learned so much this week. And am still curious on how much more I could learn if the constraints were more difficult, or there were more activities, more students, etc. But the software seems to be pretty strong and considers a lot of scenarios.
Thanks! I will check both of them, and consults with the principal. Sadly, it is in fact a mandatory constraint, he can only work on Fridays. What other things could I consider trying out while keeping his constraint?
I will then put this constraint back, and relax or check the other constraints.
Could you please tell me what constraints are a must? (maybe you can add a short comment for each.)
I will also check for clearly impossible constraints, visible by manual inspection, if this is the case, and you can show your institution that the file is impossible without relaxing some constraints (because in some cases this happens).
I deactivated the 3 activities preferred times and all the min days between activities, and it seems impossible. I think we need to relax some of the teacher not available or the 2 teacher max days per week. I will wait for your further instructions.
OK. So, the constraints that are allowed to change are the following:
Teacher not available times:
* Lut Struyf: She has Wednesdays afternoons free. What she really needs is to have one afternoon free, that can be between Monday and Thursday (not Friday, because Friday afternoons are already free for everyone)
* Eduardo Santos: He has Fridays free. What he really needs is to have either Friday or Monday free.
Activity preferred time slots:
* VERGADERING: it is currently limited to Fridays on the fourth and fifth hour (10:20-11:10 & 11:10-12:00). What it really needs is to happen on Fridays.
I know it is too few constraints to break/change and see if it works, but at least for now, they are the only constraints that can really be changed (and probably the only ones, unless it is impossible to create a schedule. If that is the case, we can also completely delete the constraint of VERGADERING).
OK, I will try now. I hope to input better constraints, which do not constrain your timetable more than necessary, as you did. If it is possible, it will come out. I will let you know as soon as possible.
Hmm... no success. I modified the constraints for the 2 teachers, LS and ES (inactivated the not available times and added the last 2 time constraints in the list - please see them).
Are there other too constrained facts like this which you added?
I will try to find a proof that it is impossible.
I obtained a very small impossible data file from your file. I kept only 7 teachers. Please see the attached. It stops at 29/58.
I will now try to think why it is impossible. You can do that, too. You can generate, and stop the timetable on the highest stage, and view the teachers' timetable.
I found why it is impossible:
The students 2KT have 27 hours per week.
But since none of these remaining 7 teachers are not allowed Wednesday, these teachers have max 26 activities in the other days.
So, it is impossible.
Edit: There might be more impossibilities like this one in your initial file.
I would advise you to begin with a possible file, and keep on generating on it as you add constraints, to make sure it is still possible.
PS: Thank you for the appreciation of the program! :)
WOW! I downloaded the file and ran it, and of course I can see that all the teachers mentioned do not work on Wednesday. If I understand correctly, it is better to start with a possible file and keep adding constraints and generating, and when the generation is not possible it is because there is a possible conflict or impossibility? I will work all night on this, loving and hating my life at the same time hahaha. I will keep you posted, thanks for the help!
If the generation goes very fast to a value and stays there for much time, the file might be impossible. But keep in mind that if the generation slowly progresses, there are timetables taking many hours and prove possible in the end. But I think your data should solve in under 5 minutes.
This method is how I did (I only did a few timetables myself - meaning from start to end).
You need to think of the interaction of the constraints.
I was preparing for sleep, but if it is a very important/urgent matter I can help you more tonight - write me an email in this case (see Contacts on the FET page or https://lalescu.ro/liviu/), in the next 30 minutes or so. I hope you saw my 2 new constraints, instead of your 2 not available. There are maybe other things which should be done in other ways, to keep things not over constrained.
Also, when the timetable is done, you can strengthen the constraints.
You are welcome!
Great, thanks! Please go sleep, tomorrow at 10am Brussels time I do have a meeting with the principal online to finalize the schedule. She uses PenaLara software, I believe it should also be impossible for her, but as the principal she has more liberty to play with constraints. I will write tomorrow, and work during the night, you have been of great and much appreciated help.
You are welcome!
Well, instead of modifying the constraints it might be also possible to swap the teachers. But i recommend that only if the not available times are needed.