Teachers early max beginnings at second hour and students min days per week

[Liviu Lalescu]

Dear all,

I had two persons suggesting me these constraints (one each):

- Teacher(s) begin the days early max beginnings at second hour (a constraint of this type exists for the students),

- Students (set) min days per week.

They can be made, but it is critical code (old or new timetables might become impossible to solve, even if they are in reality possible), and very difficult and complicated. What is your opinion, are they necessary? I think nobody else suggested them until now.

[Vangelis Karafillidis]

Hello!

I am the person who asked about the lack of the constraint "students (set) - min days per week", because it seemed strange to me, since the respective constraint for teachers has been implemented.
Regarding the Greek educational system (State Primary and Secondary Schools), the students should attend their classes every single day of the week. There are no empty days for students. I think this can be easily achieved with the existing constraints. The user should simply add the respective "min hours daily" constraints, without checking the "allow empty days". But even for different situations, the combination of other constraints "students set - max days per week", "students set - min hours daily", "students set - max hours daily", could result in the desired "min days per week", with "allow empty days" checked.
So, at least for the Greek educational system, I think there is no reason to implement this constraint.
Regarding the other constraint "teacher(s) - begin(s) early", I think it wouldn't be highly useful for the Greek educational system. At least, I never needed this type of constraint.
In conclusion, I think it's better to keep FET compatible with earlier versions. And generally speaking, it's not a good idea to invest much time in order to implement features that are not really necessary. Moreover, I think it's safer to avoid implementing features that could cause problems to FET, and only if they are really necessary to code them.

Vangelis.