multiple teachers - one group of retired people

Started by kapouer, February 22, 2009, 09:03:23 PM

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i'm trying to use fet to build timetable of several employees of a retirement house. The set of constraints concerns only the employees, as the "students" are always there... neither there is room constraint.
- employee x works y hours per week (e.g. 5 employees, each 25 hours by week)
- at least one employee should be there between 8h to 20h, every day
- each shift is 6 hours, employee could work 2 shifts by day at most
- the preferred situation is when there are two employees, the worst 1; and 3 never work together.

i'm new to fet, so it's kind of difficult to conceptualize how to adapt the concepts to the case i deal with. I've tried standard approach but it doesn't seem to be okay. I'm also trying to reverse the problem, considering employees as students, and only one virtual teacher, still, i'm going nowhere.
Any idea ?

Volker Dirr


difficult to say, because i need more information.
(for example i don't understand why a stift is 6 hours, but he work overall 25 hours. That are 4 stifts (4*6=24hours) and 1 hour i don't know were to put.)

even you wrote you have no room constraint, you should add it, because you wrote that never 3 will work together.
So add 2 rooms. And add a constraint (maybe subject "work"?) preferred rooms. So each activity is placed in a room. Then there can be maximum two activities at the same time, because you have only 2 rooms.

I think you also need constraints like:
- max hours daily
- min hours daily
- maybe also no gaps

i currently don't know how to say that there must be at least 1 worker. Maybe it is unneeded (because it is maybe impossible) if you add the room constraint.
If not: maybe ask your worker if they have preferd times and set manually 1 worker per hour.


thanks for your suggestions, i will try that.
- the thing about the shifts is that an employee could work >= 6hours.
The main problem i have is how to force the "students" to have "lessons" from 8a.m. monday to 8p.m. sunday. They have no gaps and are never alone...
Currently the guy who is doing the timetables manually is okay to say it's a pain to make them :) that's why i'm looking to use fet, which seems a very good piece of software by the way.
If you identifies one of my constraints is not currently managed by fet, i would be happy to write some code to support it, as i'm a programmer, by the way :)

Liviu Lalescu

I have an idea:

Maybe consider students=employees. Then add all the activities and add 2 rooms. Then preferred room of each activity (of your only subject, say) is room 1 and room 2, capacity of each room is 1.