Constraint Rooms cannot be used simultaneously

[vadimon]

We have some rooms, which have, for example 10 computers, and 30 ordinary tables. So we can use this room for activity tag 'pc' with 10 students, for activity tag 'practice' with 30 students and for activity tag 'lecture' with 40 students. As i think, the simpliest solution is to create three different rooms and create three 'activity tag has preffered rooms' constrains for them. But in this case this room can be used simultaneously by different teachers. In my mind, it's good to have some constraint which does not allow to use more than one room from specified list simultaneously.

[Liviu Lalescu]

Maybe the constraint activities max 1 simultaneous in selected time slots could help? If you can specify exactly the activities.

[Volker Dirr]

and other variant is to add 2 pseudo activities (no teacher, no students) just to occupy the room. of course you need to use constraint same starting time for this 2 activities and the real activity.
this variant will work, but is maybe a bit complicated to add if you have many activities.

[vadimon]

Thank you for your replies.
I do not really understand how i can use constraint for 1 simultaneous activities in whis situation.
As for idea with dummy activities - it's great, but it will work for 1 room and will not work for 2 rooms.
Take a look.
I have two students set (SS1, SS2), two teachers (T1, T2), two rooms, that can be used as PC and as Lecture (R1_PC, R1_Lec, R2_PC, R2_Lec). Two Activity Tag (PC, Lecture). I create constraint PC can use R1_PC and R2_PC, Lecture can use R1_Lec and R2_Lec).
I create Activity for same subject A1 = SS1+T1+PC and A2 = SS2+T2+Lecture. I create two dummy Activities A3 = _+_+Lecture, A4 =_+_+PC. And constraints that A1+A3 and A2+A4 should be simultaneous.
In some cases A1 takes R2_Lec, A2 takes R2_PC, A3 takes R1_PC and A4 takes R1_Lec. So two real activities occupy same room.
You can see this in attached file if using random_seed_x=1 and random_seed_y=1 (fet 23).

I hope you understand my problem and will find a way to add such room constraints (room + teacher and room + room) in future releases.

[Liviu Lalescu]

I admit I did not study thoroughly your answer, yet. But about my solution: you can choose a set of activities (in your case, all activities which will be put in those three rooms) and constrain that in all slots of the week there is maximum one simultaneous. Hmm, and now FET will tell you that you can use instead constraint activities not overlapping - so use constraint not overlapping, please. I forgot about that.

[Volker Dirr]

With 2 rooms it is no problem, because in fact the other rooms is free (used by 2 dummy activities). so it can used by the other activity.

(i am no lazy now to think about 3 room, but i think it should be the same.)

But if you have so many rooms, then you should maybe think about using one room only for pc and the other room only for lecture.

[Liviu Lalescu]

I think Volker means something like the attached file. But it is difficult to use this for larger files.

[vadimon]

Thank you for all your replies.
As i pointed earlier, the main aim of such constraint is to have ability to use room for lecture with 40 students and preserve situation, when it's used for computer practice for 40 students, while can be used only for 15. And all that by using fet's ability to check room size.
As i realized recently, i should use one room (not three) and specify maximal capacity. After that i add preffered rooms constraint for certain activity and manually specifiy rooms that is suitable by size for specified groups. As far as most of the groups and computer classes have standard size, such manual limitation will be need just some times.