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You are welcome!

Maybe in the first approach you made mistakes, because of adding many constraints, and that's why it was impossible. Or it was luck. Or: you might allow 95% for English, but you added 100% for English+French.

If you have multi-core computer, you can generate multiple on the number of cores you have = FET threads. If you have 8 core computer, generate multiple on 8 threads, it will generate 100 timetables approximately 8 times faster overall.

I obtained another solution to the same data (80% all space constraints), I attach it here. It took 1 hour.

I obtained something. Unfortunately, there are some broken space constraints. I did all the space constraints 80% and there are 15 broken such space constraints. Please see my attached file and solution.

I will try now as you said, room INF is not so important, but the other 100%. But I don't think it is possible.

I think you must shift activity id 444 one hour earlier, because otherwise is a gap for students 1 DT G2. The dummy activity I added in my k12 above did this as a trick. I think this is the error in time allocation.

About space constraints: aren't any which can be relaxed? I am trying now all space constraints 95%, but proves too difficult.

I hope I have some maybe good news:

I firstly deactivated all the space constraints, and noted that the generation locked at 514/552 (I generate multiple on 8 threads with FET-6.9.5, so it is generating 8 timetables in parallel). So I saw its id = 96 and it was related to students 1 DT. Seeing the partial timetable of the highest stage showed that there is a gap in the timetable of the students 1 DT G2. So I added a dummy activity with duration 1 to students 1 DT G2 and to my satisfaction I obtained a timetable (with very much difficulty). Note that all the space constraints were deactivated, so it might be useless. I attach, archived, the file and the solution (k12).

I am now generating on more threads with all the space constraints activated back again and that dummy activity added, but unfortunately it seems very difficult. I'll announce you if I get something, but maybe you could lower the space constraints. Or work on something from my solution to k12 above.

As a personal request, please consider and spread the word that this software is completely free/libre, and depends on kind donations/sponsorhips from the users.

Hello!

I will have a look at your file. You could have attached it here on the forum, it is a "Click or drag files here to attach them" button underneath the text. If it is too big, you can archive it.

As a first note, you use an ancient version of FET. I would advise you to update to the latest version. Also, same generator key is not recommended if the file does not solve. Also, I think you mean 552 total activities?

What constraints may I relax, if any?

Great! You're welcome!

Of course, I recommend a single constraint of this type for each teacher, for efficiency. And if that teacher is supposed to teach mandatory say 3 hours from Monday 2nd, mark with X (red) these 3 slots, min occupied = 3 is more efficient that 1 single slot/1 slot selected.

To make mandatory that a teacher has activities at Monday second hour you can use activities occupy min time slots from selection. Add all activities of that teacher, select with X (red) Monday second hour, min occupied = 1. Unfortunately, only 100% is possible.

Dear Giorgio,

I think you can use both approaches.

1) Min days between activities: take all the English and French subactivities of a specific students set and min 1 days between them with 100%. If the English teacher wants for his students set 2+1, add English subactivities 2,1; if he wants 1+1+1 add the subactivities 1,1,1. You have many constraints to add, I admit. Filter by the students set, English, add all activities, French, add all activities. This only does not work if say English is 1,1,1 95% and you prefer 1+1+1 but you allow 2+1 (in 5% of cases).

2) The trick with min gaps between ordered pair of activities works as well. You just add the maximum allowed, which is n_hours_per_day. If the activities are on different days it is OK, it is allowed for English last hour on Wednesday and French first hour on Thursday.

Please let me know.

You are welcome!

(2): If it is assumed that there are no two activities of English on the same day, and no two activities of French on the same day, you can add all the activities of English and French, 100%, min 1 days between them.

If not, I just thought of another trick: use two constraints students min gaps between ordered pair of activity tags, min gaps = n_hours_per_day. One from French to English and one from English to French. Please let me know if this works for you.

Hello, Giorgio,

Thank you for your interest! I added your words in the TODO file.

(2) - I think this can be easily solved with min days between activities or students activity tag max hours daily.

(3) - I think this can be solved with activities occupy min time slots from selection.

About (1) - yes, this is not possible currently without a new constraint. I am not sure, is it really a universally needed to be added constraint? If so, I could add it in the official FET, if not, I could make a custom version.

Unfortunately, as I have written in more places, it is very hard to live from free/libre software. There are few donations. I would be ready to add this constraint if sustained financially by a kind of sponsorship contract or work contract.

Prego, Eledibe!

No problem!

We are not closing or deleting the posts here. Maybe only modify the first post to write "[Solved]", but very rarely.

I don't understand why you did not find the option. It is right there in the dialog. A check box.

Ciao,

Scusi l'inglese:

Mornings-Afternoons mode is for Morocco, Algeria, and Vietnam. You can read the Help for this mode. If the week has 5 real days, FET will have 5*2=10 half-days.

I think you need the Official mode. You can switch to this mode from the File > Mode menu. You should not lose data, but please backup your file with what you entered so far.

If you really need M-A mode, you need to know that the first FET day = Monday morning, then Monday afternoon = second FET day, then Tuesday morning = the third FET day, and so on.