Author Topic: About 20 activities not placed after 12 hours  (Read 1206 times)

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Lizio

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About 20 activities not placed after 12 hours
« on: October 17, 2015, 02:24:49 AM »
After 12 hours of computing I still have about 20 activities not placed. I tried several times and activities not placed are always different and difficult activities or impossible ones are also different...

Any suggestion?

Volker Dirr

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Re: About 20 activities not placed after 12 hours
« Reply #1 on: October 17, 2015, 03:40:27 AM »
i used your dataset as it is (so with all constraints). But i deleted a whole year (i tested each one separated). All tables solved in a few seconds. So it look like there are no bugs in the students activity planning.

I fear it is a room problem. It is sadly very difficult to track down the bug, since you added so many single space constraints. Did you enter them all manually? It is much easier to track down and understand those bugs if you use other space constraint which sum much more. Because checking so many room constraints is very time consuming for me (and you also). You should use other space constraints like home room., preferred subject, preferred tag, ...

Volker Dirr

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Re: About 20 activities not placed after 12 hours
« Reply #2 on: October 17, 2015, 04:24:53 AM »
Sadly it can't track down a problem. Maybe it is only a very difficult dataset. In worst case you only need to wait a few years.
After that 12 hours calculating: What was the current number of placed activities. Was it close to the max number of placed activities or was is (much) less? Did you remeber if the current number of placed activities look like a "stable" number or does it change many times in the last minutes? (Between what range does it change?)

Liviu Lalescu

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Re: About 20 activities not placed after 12 hours
« Reply #3 on: October 17, 2015, 04:57:26 AM »
I removed all space constraints (without the basic ones) and it solves instantly.

I removed the max 0 building changes for students (so, only the second space constraint in your dataset) and it solved in 13 minutes (on my old computer).

So, you might want to relax a bit the rooms constraints.

Also, I tried to remove all the min days between activities constraints, and it seems that the timetable is the same as difficult as the original file.
« Last Edit: October 17, 2015, 05:10:27 AM by Liviu Lalescu »

Lizio

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Re: About 20 activities not placed after 12 hours
« Reply #4 on: October 17, 2015, 10:50:15 AM »
Thanks a lot!

A few answers:
I put all constraints manually (that is why it took me so long to finish).
I experimented that putting a space constraint to a group of students did not work for activities, I don't know why.

All space constraints are somehow mandatory as some classes have their own room (single constraint ore double for the possibility to use a pc lab) and others tour the whole school... plus the ones that tour are the only ones that are sent in the second building and these decisions were made by the council so I cannot avoid them.

The current number of placed activities looks stable after a few minutes, then it raises the maximum every once in a while. It arrives to minus 100 (more or less) activities placed in a few seconds, then it arrives to minus 30 in about 30 min and minus 20 in 5 or 6 hours, during all the time the placed activities are between 2 and 5 less than the maximum and not changing quickly (sometimes they stay for hours).

I have built the data adding activities and trying timetables and it would colse in few seconds as long as I did not place the last 10 subjects that are "Educazione fisica" and "informatica", but when I added those activities I also added the time constraint for all students to begin early and to have min 5 hours per day (those constraints were impossible without completing the data....

I also tried to add the time constraint of early beginning for all students without having completed the activities and FET could not close the timetable after 17 hours...

I'm thinking about splitting some 2 hours activities into 1 hour activities with time constraint not at 100% but at 95% so that FET can decide when to put 2 hours one after the other, would this help?

If I put the minum days between subactivities to 1, what percentage should I put to let FET decide when putting 2 hours one after the other and when not, but without the possibility of having 3 hours in the same day?

Liviu Lalescu

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Re: About 20 activities not placed after 12 hours
« Reply #5 on: October 17, 2015, 11:08:50 AM »
If I put the minum days between subactivities to 1, what percentage should I put to let FET decide when putting 2 hours one after the other and when not, but without the possibility of having 3 hours in the same day?

Consecutive if same day = false, min 1 days, 0%, then constraint students / teachers activity tag max hours daily. I think this is a good solution.

If you add n activities in a min days constraint which has consecutive if same day = true, FET will never place 3 of them on the same day. Unfortunately, it does not work for consecutive if same day = false.

Lizio

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Re: About 20 activities not placed after 12 hours
« Reply #6 on: October 17, 2015, 11:18:47 AM »
If you add n activities in a min days constraint which has consecutive if same day = true, FET will never place 3 of them on the same day. Unfortunately, it does not work for consecutive if same day = false.

This is a great news! So if I want to have couples of hours of a subjects around and not triplets and I need couples to be consecutive, I only have to set all subactivities in a min days constraint with consecutive if same day=true and I can place any percentage and this will always work and tell FET how strongly I'd like to have single hours... if for example I can manage to have 3 couples of hour for a 6 subactivities of 1 hour subject, I can put the 6 subact. in a mi days constraint with consecutive=true and percentage 50% and if I strongly prefer for another activity not to have couples, I can do the same but puttin 95%...

I'll try to modify my data like this and see if it closes the timetable!

Thanks a lot!!!

Liviu Lalescu

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Re: About 20 activities not placed after 12 hours
« Reply #7 on: October 17, 2015, 11:31:21 AM »
Yes. If it does not matter, you can add weight = 0%.

Lizio

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Re: About 20 activities not placed after 12 hours
« Reply #8 on: October 18, 2015, 02:58:38 AM »
Yes. If it does not matter, you can add weight = 0%.

 :D

Lizio

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Re: About 20 activities not placed after 12 hours
« Reply #9 on: October 20, 2015, 10:50:36 AM »
Ok, here are some news:

-I've loosed some constraints on subjects letting FET decide if putting 1 or 2 hours
Process fastened in reaching minus 20 activities but then nothing.

-I've found an error on a room for one activity
No changes in timings

-I've deactivated all space constraints and my timetable closes in 4 seconds

-I've activated space constraints beginning with fixed rooms for activities
It closes in 6 seconds

-I've activated space constraints for activities that share laboratories
It closes in 8 seconds

Now the state of art is that all constraints for 1st, 2nd and 3rd classes are activated, all constraints for one class 4th year and one class 5th year are activated and all constrants for language lessons and informatics and physical education are activated.

It closes in 8 seconds.

Now I should activate constraints for 6 classes of the 4th year and 3 classes of the 5th year.
Activating 5 out of the 6 classes of the 4th year it closes in 2 or 3 minutes if I activate the 6th class it behaves like everything is activated.

These last classes are the ones that do not have an assigned place and they tour all rooms (they should be easier to place), but are alse the ones that use rooms of the secondary building and there are time constraints on tranferring from a building to the other and also for classes that cannot be tranferred in the single day...

I have noticed that as long as FET could place activities in one building, everything goes right, as soon as the second building is needed here come troubles and FET tries to place as less activities as possible in the second building.

Any suggestion?

Liviu Lalescu

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Re: About 20 activities not placed after 12 hours
« Reply #10 on: October 20, 2015, 12:33:50 PM »
I have noticed that as long as FET could place activities in one building, everything goes right, as soon as the second building is needed here come troubles and FET tries to place as less activities as possible in the second building.

Any suggestion?

FET only respects the buildings constraints which you have added.

Lizio

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Re: About 20 activities not placed after 12 hours
« Reply #11 on: October 20, 2015, 01:49:44 PM »
Yes, is there any way to make FET try to use some rooms first?

In that case I would make it use the second building first and probably completing with the first one would be easier.

Liviu Lalescu

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Re: About 20 activities not placed after 12 hours
« Reply #12 on: October 20, 2015, 11:25:55 PM »
Yes, is there any way to make FET try to use some rooms first?

In that case I would make it use the second building first and probably completing with the first one would be easier.

I think the answer is no.