How to get a synchronous/even timetable for teachers

[xing]

Hi everyone,

Assume T teaches Physics for two groups gC and gD, separately, 3 times a week, one hour at a time. That means T works 6 hours a week. The contents for gC and gD are identical so that T only needs to make three teaching plans a week. In each plan, T should finish teaching both gC and gD for one hour each in arbitrary order, either consecutively or not. Only after T completes a teaching plan can the next one be started. For example, week timetables like
1. gC...gD...gD...gC...gCgD..
2. gDgC...gD..gC...gC..gD
3. gC..gD...gD..gC...gC...gD..
are all even or synchronous. But week timetables like
4. gC..gC..gD..gD..gC..gD..
5. gD..gD..gD..gC...gC...gC..
are not.

I tried to use the Constraint two activities ordered but it's a very strong constraint. If I use it for all teachers, it's a heavy job cause there are many possible activity combinations, and it's hard to get a timetable with such many constraints. Has anyone encountered the same situation or any ideas?

Thanks in advance,
Xingxing

[Liviu Lalescu]

It might be possible, but as a customization.

[Volker Dirr]

If you have an easy timetable you might try it.
But if you have a difficult timetable or other (missing) constraints, then i don't recommend it.
In many cases it doesn't make sence to care about such a nice order. Why? Because in practice such a nice order won't hold long.
As soon as the teacher is ill, a group is on a trip, there is a bublic holiday, ... the order will be disordered.
So a good teacher always able to "strech" one hour so get order again. So in fact he can do the some trick also the first day. So even an unordered timetable will get ordered by that.

[xing]

It might be possible, but as a customization.

Need to add new constraints?
This constraint may be very complicated, because it is possible that one teacher teaches multiple subjects and each subject has multiple classes. In addition, there are many combinations of related activities that can meet the requirements. Its very flexible. What do you think about it?

[Liviu Lalescu]

I thought it would be possible to add a constraint with a group of activities for the two sets of students for each teacher.

[xing]

If you have an easy timetable you might try it.
But if you have a difficult timetable or other (missing) constraints, then i don't recommend it.
In many cases it doesn't make sence to care about such a nice order. Why? Because in practice such a nice order won't hold long.
As soon as the teacher is ill, a group is on a trip, there is a bublic holiday, ... the order will be disordered.
So a good teacher always able to "strech" one hour so get order again. So in fact he can do the some trick also the first day. So even an unordered timetable will get ordered by that.

The actual situation in our school is that teachers prefer to synchronize the course progress of different classes they teach as much as possible. This can reduce the frequency of their lesson preparation. Synchronization is their main criterion for evaluating the quality of the timetable.
It's hard to "strech" one hour to get order in some timetables, such as [...gC...gC...gD...gC...gD...gD...] gC leads gD one hour every week.

[Volker Dirr]

I am 20 years teacher now. It is not difficult to remeber such things for a single week. The stupid stuff is that even a perfect timetable with perfect order will disorder very fast if one groups has one hour less than the others. Just because of a public holiday, an missing student, a class teacher that need one with that group, a school trip, teacher itself is ill, .. .. There are so many things in a teachers' life that will disorder the perfect order very fast. I think most skilled teacher knows how to strrech those  situations. If this is the last missing constraint in your timetable, then of course try to add it. But i recommend to add other constraints first. Think for example about a good students timetable. Most timetable makers always think about good timetables for teachers, even timetables should be good (also) for students.

[Volker Dirr]

I forgot to write why i think it is easy to remeber. Not because my brain is perfect. Sometimes I am also stressed/confused.
But I can still get the hint very fast.
If i enter a room and I am not sure if I need to teach the 1st, 2nd or 3rd lesson of this week now and i also forgot my notes, then I use one of the following tricks:
1. Just go to the teachers desk and read what I wrote into the book last hour (We need to write the topic and sign into the class-register).
or
2. Just say "Good morning. What have we done last hour?" By that i can rate a student and also remeber at the same time.
or
3. Just say "Good morning. Lets start. Please open your notebook.". Even if the notebook is more then 1m away and even i can see it only 180° turned around, I can still remeber what i have done last hour. Of course you should view to a notebook of a not too bad student.

[xing]

Thank you Liviu and thank you Volker for your suggestions. Maybe I care too much about the teachers' opinions, it is difficult to schedule a timetable that everyone is satisfied with. I will think of other ways to solve this problem.

[Volker Dirr]

yes. That is in fact a problem that i learned later. There are same teachers that never complain, while other complain about very very small things and a few of them also ask for impossible stuff. My favorite request of a teacher was a guy that must teach 21 hours per week (that was his request in his working agreement.) But then he came to me and said: (I have 21 hours per week,) but i can't work at .... . I counted that slots and there were only 20 free slots left :-) Funny guy.
Also funny: A guy requested to have the 1st hour free. So i set him 1st hour always free. 1 week later he complained why he has never lessons in the 1sh hour.
There are several examples like that.

[Vangelis Karafillidis]

Many teachers like demanding and demanding... and demanding. It's something like a sport or hobby for them. Most of the time, they don't care how many hours you should spend in order to satisfy their crazy, useless and sometimes impossible demands. I think that you should center on your task. And your task is to schedule a functional and fair timetable for your school. Just this. So, you should just care about the constraints that are really needed for your school.