Venue occupation/size

[Frans]

Dear Liviu

If one allocates a too small venue to a specific group, Fet warns the user immediately. I do have another situation and just want to know if it is possible to handle it in the same way. It probably has to do with the algorithm. I will explain the issue with an example:

Say Room 1 is of size 100 and is available for 40 fet hours per week. Further suppose 38 fet hours are already used. (The user does not know this.)

Room 1 has been allocated to an activity with 90 students and for 6 Fet hours. In other words there are 4 periods short, size ok.

It seems to me that in such a case, and I might be wrong, Fet goes into a loop. There is no problem with the activity itself, but with the availability of hours.

Currently I do not know if it is the venue or an impossible activity. Now the question: Is it not possible that Fet can warn the user about this and stop executing?

The reason why I asked this is that at a University something like this will come in very handy. Instead of tracing a non existent error, I know immediately that is a venue.

At the moment what I do is to use the save highest stage timetable and then the first thing that I check is venue availability.

My apologies if the question does not belong here.

Kind regards.

Frans

[Liviu Lalescu]

Hello, Frans!

Your assumption is right, FET will cycle (loop) endlessly.

In usual situations, I advice people to solve firstly the time allocation, then space allocation.

This seemed like a situation which would not show up (in usual situations), but it seems that I was wrong.

There are many variants for impossible situations like that, because it depends on weights and constraints. In the past, I chose to leave these problems to the user. I hope in the future to correct such situations. It is not difficult work, but error prone (for instance, I may wrongly state that a situation is impossible, and the user will be puzzled: why) and also there are a lot of variants to analyze.

So, you say this: room R, has some not available periods with 100% (remain 9 hours with not available under 100%), and activities A1, A5, A6 have sum of durations 10 and preferred room 100% to R, this is an impossible situation for your case?

I'll think about it, maybe I'll come up with a solution.

[Frans]

Thanks Liviu for the quick reply.

What I do is to divide our venues into Large, Medium, Small and Labs using activity tags. To these activity tags I add the appropriate rooms. The activity tag I add then to the activities in the activitie screen. Yes my percentage is 100% because it is the only venues I have and the activity must be scheduled in one of them. If it is not possible then a timetable is impossible.

I for example run fet through the night with no solution. The next morning, for some or other reason, I just changed the size for one group from large to medium size and the timetable was solved in less than 10 minutes. If I knew before the time the only problem was space then I could have made the change immediately.

Liviu one other thing: If I add for example two activity tags with rooms, seperate rooms, say tag Medium and tag Large to an activity, Fet gives a space error. If I leave only one of them, does not matter which one the timetable is solved. (The group can fit into any of the venues and there are sufficient space.)

So it seems to me that in this case one can only add one activity tag to an activity if it has to do with space. Am I correct? It is however,not a problem.

Thanks.

Frans

[Liviu Lalescu]

Thanks Liviu for the quick reply.

What I do is to divide our venues into Large, Medium, Small and Labs using activity tags. To these activity tags I add the appropriate rooms. The activity tag I add then to the activities in the activitie screen. Yes my percentage is 100% because it is the only venues I have and the activity must be scheduled in one of them. If it is not possible then a timetable is impossible.

I for example run fet through the night with no solution. The next morning, for some or other reason, I just changed the size for one group from large to medium size and the timetable was solved in less than 10 minutes. If I knew before the time the only problem was space then I could have made the change immediately.

First of all, let me tell you this: there is a minor bug in FET-5.12.0, solved in future 5.12.1 (to be out in 2-5 days probably). If you modify a students set's number of students, the activity will modify these visually, but not internally. You must save file and open it again and regenerate. I am very sorry! :-( . If you use activities with specified number of students (>=0), then you won't meet this bug. Only if you modify the number of students in a year, group or subgroup and your activity uses -1 for number of students (automatically compute).

Maybe this bug affects you? This bug is present for a very long time now (>1 year probably), but nobody reported it, I discovered it a week ago by chance.

I just want to tell you that your problem is impossible to diagnose automatically. Because there are so many combinations of rooms. If you used only one preferred room with 100% for more activities and wanted to see the rooms exhaustion for these rooms, it would have been possible (in fact, because of your post, I have implemented a test to detect such problems). But this test is not good for you. I'll think whether to leave this test active, because I am afraid of bugs and anyway this test seems not very useful.

I advise you to firstly allocate the times, then the space. You could make all space constraints have weight 0% for this matter (the preferred rooms constraints accept 0% weight).

Liviu one other thing: If I add for example two activity tags with rooms, seperate rooms, say tag Medium and tag Large to an activity, Fet gives a space error. If I leave only one of them, does not matter which one the timetable is solved. (The group can fit into any of the venues and there are sufficient space.)

So it seems to me that in this case one can only add one activity tag to an activity if it has to do with space. Am I correct? It is however,not a problem.

Thanks.

Frans

Every constraints must be respected. So, if you have 100% for Medium to RM1 and RM2 and 100% for Large to RL1 and RL2, then an activity with these 2 tags is impossible to place in a room (because intersection of {RM1,RM2} with {RL1,RL2} is void). You must find other solution. Maybe 100% for Large to four rooms: RM1, RM2, RL1, RL2 would be a solution (and keep the 100% Medium to RM1 and RM2).

[Volker Dirr]

Liviu one other thing: If I add for example two activity tags with rooms, seperate rooms, say tag Medium and tag Large to an activity, Fet gives a space error. If I leave only one of them, does not matter which one the timetable is solved. (The group can fit into any of the venues and there are sufficient space.)

So it seems to me that in this case one can only add one activity tag to an activity if it has to do with space. Am I correct? It is however,not a problem.

If you want to solve that, then you can think about this:
do an activity tag "large", with a space constraint to large rooms and tag all needed activities with that.
do an activity tag "small", with a space constraint to small rooms and tag all needed activities with that.

So now you need some (small) activities that can be in small or large room because in other case timetable is impossible?

add a new activity tag with "small/large" with a new space constraint to small and large rooms ans tag some activities with that.

would be nice if you can sent us you data file, so we can check a bit better about possible checking rotines. if you don't want to publish official, you can also sent private to Liviu or me, we will keep it private.

[Frans]

Liviu

there is a minor bug in FET-5.12.0, solved in future 5.12.1 (to be out in 2-5 days probably).

I want to apologize not for reporting the above as I am aware of this for sometime. For this reason I change group sizes where the activities are added. (Is this not what you changed in the latest snapshot?)

because intersection of {RM1,RM2} with {RL1,RL2

Thanks now I understand.

Kind regards.

Frans.

[Liviu Lalescu]

Liviu

there is a minor bug in FET-5.12.0, solved in future 5.12.1 (to be out in 2-5 days probably).

I want to apologize not for reporting the above as I am aware of this for sometime. For this reason I change group sizes where the activities are added. (Is this not what you changed in the latest snapshot?)

The latest snapshot (from 4 January) fixes this bug, could you please check that it is solved? Also, check that if you have overlapping sets, if you change the number of students in one place, it changes in all places where this set appears (only if you have overlapping sets).

The snapshot contains the same interface as before, you can set the number of students for an activity manually or automatically computed from the students sets' number of students. Just that now if you modify a students set, the number of students in the activities with automatic are correctly updated, internally.

I am not sure what do you mean by "(Is this not what you changed in the latest snapshot?)", but please check the latest snapshot and tell me if the bug is solved.

You mean that you don't use activities with -1 students (automatic), but instead use manually number of students for activities?

[Frans]

Volker, thanks

add a new activity tag with "small/large"

This is exactly what I do at the moment creating activity tags for Small, Medium, Large and All and it is working.

While we are on this topic (just asking).

One can add space constraints at many places for example where one adds activities and then using the menu for preffered rooms for subjects, students etc. I refer now to the menu constaaints.

What is the chances that one can add an activity tag containing rooms for a studentset for example. Currently one as to add the rooms one by one to the studentsets. It will be much quicker using an activity tag. This probably also have to do with the algoritm and I do not know if it is possible.

(Let me know if I am asking to many questionss!!!!)

would be nice if you can sent us you data file,

I do not have a problem with this. I am still busy with the final touches to the final timetable. When finished I will post again to hear what to do.

Some info on the timetable if you are interested:

The timetable is for a University in SA. The timetable consists of 1608 activities with more than 3 000 fet hours, app. 300 teachers and 4 different campuses. (Due to distance one can only lecture on one campus for a specific day)

I therefore make use of the following constraints:
Building changes for teachers (leturers).
Same starting times.
Preferred time slots.
Home Rooms.

and many more. The first 563 activities are very difficult to schedule and take some time. So I scheduled and lock these activities. Now I am busy scheduling the rest of the 1608 activities.

Currently it takes between one hour and one and a half our to schedule the easier activities. Once finished I will unlock everything to see how long it will take.

So if the file can be use to test new FET features or to improve existing features I will be very glad to let you have the file. Just be patient it can take another two to three days to finalize.

Kind regards.

Frans

[Frans]

Liviu

could you please check that it is solved

Yes, I will do it immediately because it will save me a lot of "pain". Thanks for this. Will let you know.

I am not sure what do you mean by

I was referring to the last snapshot of 2009.

You mean that you don't use activities with -1 students (automatic), but instead use manually number of students for activities?

Yes but only when I had to change a group size. With the new snapshot that will not be necessary.

Frans

[Liviu Lalescu]

What is the chances that one can add an activity tag containing rooms for a studentset for example. Currently one as to add the rooms one by one to the studentsets. It will be much quicker using an activity tag. This probably also have to do with the algoritm and I do not know if it is possible.

(Let me know if I am asking to many questionss!!!!)

You could add an activity tag with all allowed rooms for that students set, and add this activity tag to the activity, why can't you do that? You can have any number of activity tags to an activity. Activity tag ATS1, with allowed rooms R1, R2, ..., Rn, where R1..Rn include all allowed rooms for this students set and they must be large, medium or small (all categories). Why can't you use this?

Not at all too many questions :-)

I do not have a problem with this. I am still busy with the final touches to the final timetable. When finished I will post again to hear what to do.

Any .fet file is good, for testing and for putting in the FET examples (if no copyright problems). You may also let us and others know about your FET experience in the feed-back board and/or guest book.

[Frans]

Liviu

I think my question was not very clear and I try again.

I refer to the Data menu, space constraints and say students, set of home rooms and then add. In this box I select the students and then the individual venues.

If I for example already defined an activity tag for Large rooms, I want to add the activity tag instead of the individual venues.

Now that I think again I doubt if it will be possible, because FET has to make a distiction between general activity tags and "room" activity tags as the room activity tags must also appear in the rooms list so that it can be selected. How will FET know this.

Next I time I will first analyze  before posting. (It is possible that I am only lazy but if you do have a few hundred different groups something like this will be time consuming, selecting venues.)

Frans

[Liviu Lalescu]

Liviu

I think my question was not very clear and I try again.

I refer to the Data menu, space constraints and say students, set of home rooms and then add. In this box I select the students and then the individual venues.

If I for example already defined an activity tag for Large rooms, I want to add the activity tag instead of the individual venues.

Now that I think again I doubt if it will be possible, because FET has to make a distiction between general activity tags and "room" activity tags as the room activity tags must also appear in the rooms list so that it can be selected. How will FET know this.

Next I time I will first analyze  before posting. (It is possible that I am only lazy but if you do have a few hundred different groups something like this will be time consuming, selecting venues.)

Frans

I understand now. This idea was suggested before, I'll add it in the TODO, but it is a bit complicated.

Suggestion: the rooms are kept in the list box. So, you may try to add constraints in a certain order which keeps the rooms changes to a minimum. So, if you have S1(R1,R2,R3), S2(R2,R5) and S3(R1,R2,R3), add S1 with 3 rooms, then change S1 to S3, add constraint, then add S2 (only now you need to change the rooms).

[Frans]

So, you may try to add constraints in a certain order which keeps the rooms changes to a minimum.

Currently I am doing this.

Thanks for all the advice today.

Fet just finshed setting the timetable so now I must check.


Fans.