OLD - FET-6.4.0 snapshot - this branch will NOT be abandoned (as of 16 May 2022)

Started by Liviu Lalescu, April 22, 2022, 02:58:03 AM

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Liviu Lalescu

I have put a snapshot. From the ChangeLog:

    - Added the option to lock activities to their scheduled day, useful for timetables which change over the year, due to teacher arrival/leaving. This option is available in the students/teachers view timetable time horizontal dialogs. Suggested by Vangelis Karafillidis and Alexey Chernous.
    - Improved the behavior of the timetable view students/teachers/rooms days horizontal dialogs, as suggested by Vangelis Karafillidis.

The link, as usual: https://lalescu.ro/liviu/fet/download/test/

Please let me know.

Liviu Lalescu

Unfortunately, I need to abandon this branch and revert to FET-6.3.3. The reason is that for my second file on which I tried the new feature I met a very bad behavior: I generated a timetable (usually in ~1 minute), and locked the activities to days. Then the resulted file is usually cycling.

I attach the original file (from Romania/Pedagogic-High-School-Tg-Mures), the modified cycling file (kped.fet) and a sample cycling random seed.

Vangelis Karafillidis

#2
I confirm that I encountered similar problems with this file. After generating, then locking all activities in their respective days and re-generating multiple timetables, in most cases FET seems to be stuck after around half a minute. But, other testings with other files and with few activities locked in time, more activities completely unlocked and many activities locked in their respective days, FET behaved very well and generated multiple timetables.
Liviu, most likely the problem occurs when ALL the activities are locked in their respective days. In real-life timetabling problems, this situation is virtually impossible to occur.
Also, much time ago, I re-generated multiple timetables from a generated one, by unlocking the activities of the 1st day (and keeping locked all the other days) and generating, then unlocking the activities of the 2nd day (and locking all the other days) and generating. This resulted in new timetables with all the activities being locked in their respective days. It's really strange that FET behaves in a different way when all activities are locked in their respective days....

Liviu Lalescu

I am so sorry, Vangelis, but this potential problem is a big one. It appears because of the algorithm.

Vangelis Karafillidis

Most likely, the latest snapshot works very well for real-life timetabling situations. It seems that only the situation where all activities are locked in their respective days cause problems in generating modified timetables. But, I can't think of a real-life timetabling situation which demands ALL the activities to be locked in their respective days.
My opinion is that this snapshot could be really useful for users that need to modify their existing timetables.

Liviu Lalescu

Unfortunately, I think that this problem might appear in other files as well, and in partial files as well. Also, the users who don't know this problem might try to lock to days all the activities.

Liviu Lalescu

I decided to add this feature in the official FET-6.4.0-snapshot. It works on most files, only on my contrived file it has problems (even the problematic unlocked file is contrived).