Author Topic: Help with this impossible timetable  (Read 1084 times)

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sebholl

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Help with this impossible timetable
« on: February 08, 2015, 08:38:01 PM »
Hi, first of all i want to thank you for putting the effort in making this gem. Ive googled many doubts and problems and always found a solution almost always with staff answers. Thanks for the support as well.

No into my problem. I have this timetable that i know is impossible to solve. But, i want to use the power of FET to get to the highest allocation of activities possible and then locate problemtic teacher availability contraints and act upon them.

The thing is, ive tried relaxing restrictions as much as i could, but fet always stops allocating activities at 193 of 284. It then lowers them up to arround 115 and gets stuck.

Ive analyzed quite a few of the leftover activities generating a highest stage timetable (193 activities) but the strange thing is that ive found a bunch of activities that could easily be allocated given current restrictions.

I,ll attach the file and wait for your input to see if a can try anything that can get me closer to the 284 activities i need to allocate so i could easily finish them off by hand.

Thanks again, great piece of software.




Liviu Lalescu

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Re: Help with this impossible timetable
« Reply #1 on: February 09, 2015, 04:28:22 AM »
FET will place activities in order, starting with the most difficult ones. If you reach 193 placed activities, it means that the first 194 activities are impossible and FET will not go any further. So, I just inactivated activities in turn (inactivated the difficult activity as reported by FET). After inactivating 4 activities, I obtained a solvable file, which I attach.

sebholl

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Re: Help with this impossible timetable
« Reply #2 on: February 09, 2015, 06:58:23 AM »
That was easier than i expected. Didnt think of that. Thanks a lot

sebholl

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Re: Help with this impossible timetable
« Reply #3 on: February 09, 2015, 12:59:39 PM »
Hi Liviu, i tried your solution, looking for a better TT i can work with.

The problem:

Almost all impossible activities are with a student group with the following layout (small group).

Group Humanities.
Group Economics.
Both groups together for common activities.

Deactivating impossible common activities in this groups leads to different uncallocated periods in each group. This makes very hard finishing the TT by hand.

Question: Is there a way i can prioritize the allocation of all slots in this group first? I would then have impossible activities on groups with no common activities and it would be simpler to solve.

I hope you understood the problem

Thanks once again
Sebastian



Liviu Lalescu

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Re: Help with this impossible timetable
« Reply #4 on: February 09, 2015, 01:11:57 PM »
Do you mean you want to place firstly a group of activities? Please activate the advanced "Group activities in initial order" and press the Help button there and use it.

sebholl

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Re: Help with this impossible timetable
« Reply #5 on: February 09, 2015, 01:35:54 PM »
Im gonna try that! Thanks for the quick answer

sebholl

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Re: Help with this impossible timetable
« Reply #6 on: February 09, 2015, 07:24:19 PM »
It worked like a charm. Thanks, you really saved me a lot of time and headaches. It even returned a better TT starting with those activities.

Will keep this for future runs. Extremely usefull

Liviu Lalescu

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Re: Help with this impossible timetable
« Reply #7 on: February 10, 2015, 12:22:24 AM »
I'm glad it worked :)