I really don't know how to do it and so I need help here, thanks a lot:
day per week = 5
no. of activities = 4
no. of duration = 5
That means I want to schedule 5 lessons in 4 days (2,1,1,1),
however, I want the day with double lessons to be non-consecutive,
thanks!
I did not add a constraint to force activities to not be consecutive. Only you and another person recently suggested this.
However, I think I have a good solution for you: say A1, A2, A3, A4 are one hour, in different days, and A5 one hour in the same day as A1. Add constraint activities same starting day, A1 and A5.
Suppose A1 is the first in the day and A5 is the second (after A1, separated by at least one hour). Then add a dummy activity A6, duration 1, no teachers, no students. Add constraint 2 activities consecutive, A1 followed by A6. Add constraint activities not overlapping, A5 and A6. This is phase 1.
Phase 2: add a dummy activity A7, duration 1, no teachers, no students. Add constraint 2 activities consecutive, A7 followed by A5. Add constraint activities not overlapping, A1 and A7. This phase 2 might lead to A5 before A1, but this I think is no problem for you.
Or, a better phase 2: add constraint 2 activities ordered, first A1, second A5. In this case A1 will be always before A5.
You may find a simpler solution, I did not think too much when writing this.
I hope this works for you. Please let me know.
It is a complicated solution. A simpler solution might be to add A1, A2, A3, A4 as a split activity, then A5 single, then constraint activities same starting day, A1 and A5, and hope A1 and A5 will not be consecutive.
Thank for very much for your help!
I would like to know will the dummy activities filled in the time-table? (because I got a full time-table, no free lesson for students)
besides, your suggestion is great but I got a lot of such non-consecutive classes which means I have to add a tons of constraint.
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I would like to know will the dummy activities filled in the time-table? (because I got a full time-table, no free lesson for students)
No problem with these activities, because they have no teachers or students sets.
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besides, your suggestion is great but I got a lot of such non-consecutive classes which means I have to add a tons of constraint.
I am sorry, but your request is so different from normal requests I could think of. Why can't you allow the activities to be consecutive?
Thanks again for you reply.
Why do we need non-consecutive classes?
Actually I do think it is stupid because you have to take the lesson eventually. The reasons is the administration of my school thinks that take double lesson is too long for teachers and students (55min + 55min).
OK.
Another solution (a trick) might involve dummy buildings. Add room R1 (Building B1) and room R2 (Building B2). Add 2 constraints activity preferred room, (A1, R1) and (A2, R2). Add constraint min gaps between building changes for students (or for teachers) -> 1.