suggestions for multiple weeks timetable (not the 120 days custom version)

[GEA_user]

Hello  ,
I'm encountering a problem in the same context that I don't know how to handle. I've attached a minimal file that illustrates my issue.
Let's say that teacher1 wants to have the same time slot every real week (except in exceptional cases) with the students1 group, and that Thursday in week2 is a holiday. Given that teacher2 teaches chemistry to the same group, students1, in two 3-hour blocks—either on Monday, Tuesday, or Thursday in week2.
My constraints are as follows:
teacher1's activities start at the same time (90% of the time(
minimum days between teacher1's activities is 5 (95% of the time)
maximum days between teacher1's activities is 25 (100% of the time)
The proposed percentages are to prevent FET from searching for a solution for too long.

The problem is that sometimes FET will propose a solution where Teacher1 has classes in the same time slot every actual week except week2 which is the expected behavior—but sometimes it may also propose a solution with classes on Tuesday in week1 and on Mondays in weeks 3 through 6.
To avoid this, I haven't found any other solution than to remove teacher1's activity in week 2 from the constraint "minimum days between teacher1 activities is 5 to 95%" and to add a constraint of the type "minimum days between teacher1's activities in week1 and week3 is 10."
However, I don't know in advance whether Teacher1 will have a problem with the holiday in week2; this is due to the scheduling of teacher2's class, which is constrained by the holiday.
In other words, I feel like I have to, by default, perform this adjustment for all activities in a given week whenever there's a specific issue like unavailable students or a holiday (which happens, in my case, every other week).
How can I use Terms mode to simulate a constraint like this: teacher1's activities are on the same real day (95% of time)?
Best regards,

[Liviu Lalescu]

Hello! 

I think new development would be needed for this, in maybe a new constraint to do this: specify in the constraint a set of n activities, and say that at least n-1 of them must be on the same real day and at the same hour, in the Terms mode.

I'll write this suggestion in the list of suggestions, the TODO list.

[GEA_user]

So that confirms what I thought—it's not possible at the moment.
Thanks for adding it to the TODO list.

[Liviu Lalescu]

You are welcome!