Constraining a set of rooms to different time+day

[mma]

Hi,

Is there a neat trick for saying that I do not want a set of rooms used at the same time. For example, if room 1 is in use, I do not want room 2 and room 3 to be used, but if room 1 is NOT in use, then it is OK to use room 2 and/or room 3?

Set 1: (room1)
Set 2: (room2, room3)

Can use rooms from either set at the same time+day, but not both.

Thanks for your help.

[Volker Dirr]

So your activity in room 1 also need room 2 and 3.
You must add 2 dummy activities that use room 2 and 3 and conect this dummy activities with the activity that use room 1. (constraint same day+hour)

[Garouda2]

I have a similar problem (maybe the same, it's not very clear). Students are divided in two streams, Arts and Science. Let's take Grade 10 as an example. For English classes, they are divided according to their proficiency in English, say low and high (could also be low, middle, high). For English all Grade 10 students are divided into two groups, so I need two teachers and two classrooms. FET allows you to assign two teachers to the same activity and solve the problem nicely, but does not allow you to assign two rooms to one activity...
If you use set of rooms, you can assign two rooms, but there are conflicts with other activities using that room at the same time...
How can this be solved?
Thank you

[Liviu Lalescu]

I think the same answer as Volker's above: If you need an activity to occupy two rooms (at the same moment, of course), add to the initial activity a "twin" activity, with the same starting time (day+hour), no teachers, no students (so that there are no basic compulsory time constraints conflicts).

Yes, many requested this for the official FET, I mean an activity to occupy more rooms (see the entry 114 in the TODO file for FET-5.18.0). I'll think about it.

[Garouda2]

In that case how will FET be able to calculate a timetable?
Starting time day+hour is what I am looking for. To get a timetable, I give the students' set, the subject, the teacher(s) and now the room(s) as parameters and FET finds out the day+time.
I mentioned English and the proficiency level groups, but a similar situation appears with elective subjects.
E.g. Arts students can chose between French and Chinese. So, at the same time, the same students' set will be in two different rooms, with two different teachers...
In the past, I had many rooms at disposal, so I did not need to find an optimal occupation. It was easy then.

[Liviu Lalescu]

As I wrote above, say you have activity A1 ( S1, T1, T2 ) - where S1 is a students set and T1 and T2 are teachers. Add a dummy activity A2, no teachers, no students, same starting time with A1, and add preferred rooms for A1 and A2.

[Garouda2]

Thanks Liviu for your answer.

I must miss something, how can I tell FET that A2 must have the same starting time as A1.
Is it by using 'two activities are grouped' or 'A set of activities has the same starting time' ? Anyway, I'll try both.

Thanks again.
(Another situation where we could need this, or another way to explain the problem: Assume you have two streams Arts and Science. Your students, both streams, are in the same classroom (homeroom) and there are core subjects for both streams. There are also specific subjects and students must move to another room. At the same time S1 splits into S1Arts and S1Science. Let's say S1science remain in the initial room and S1arts have to move to another room, which is not assigned in advance, but part of a set of rooms. Let's S1 be a Grade 10 set, at the same time, a similar situation can happen with S2 which could be a Grade 11 set. They all want to access the same group of rooms. I'd like FET to assign a room avoiding conflicts with other students sets.)

[Liviu Lalescu]

Thanks Liviu for your answer.

I must miss something, how can I tell FET that A2 must have the same starting time as A1.
Is it by using 'two activities are grouped' or 'A set of activities has the same starting time' ? Anyway, I'll try both.

A set of activities has the same starting time

Thanks again.
(Another situation where we could need this, or another way to explain the problem: Assume you have two streams Arts and Science. Your students, both streams, are in the same classroom (homeroom) and there are core subjects for both streams. There are also specific subjects and students must move to another room. At the same time S1 splits into S1Arts and S1Science. Let's say S1science remain in the initial room and S1arts have to move to another room, which is not assigned in advance, but part of a set of rooms. Let's S1 be a Grade 10 set, at the same time, a similar situation can happen with S2 which could be a Grade 11 set. They all want to access the same group of rooms. I'd like FET to assign a room avoiding conflicts with other students sets.)

I am not sure, is this situation solved by Volker's and my answers above, or we need to think of something else?

[Garouda2]

Thanks a lot Liviu, it works. I created another activity for the same subject, no students no teacher. After that I used the function
you suggested (A set of activities has the same starting time) then I assigned the rooms to the activities. I worked step by step, generating timetables even if all the job was not completed to identify potential problems and got finally a solution.
Your program is amazing. 
The last case I mentioned in fact doesn't need any adjustment, it can easily be solved because there are two distinct activities.

Thanks again.

Bernard (Thailand).
I tried to make a small donation (out of my pocket, the school won't pay and here we do not earn European salaries...)
but those in charge at Paypal  don't let you edit your credit card number during the process  , so I have to fix this before...)