Min hours daily with an activity tag for a students set

Started by alex, December 04, 2015, 09:29:08 PM

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Is there ANY way to achieve a constraint like: "Min hours daily with an activity tag for a students set"? The polar opposite (max hours) is available in FET, but what about MIN HOURS? I was thinking of the equivalent of inserting for each day the constraint "a set of activities occupies max time slots from selection", but this might severely slow down the whole process...

Thanks a lot!

Liviu Lalescu

In each day, or only in non-empty days?

Please try with activities occupy max time slots from selection, it will not slow down the process. This constraint is highly optimized.

Please let me know the result.

It would be possible to add this constraint, but I am reluctant, as it would not be best implemented. Maybe as a custom version, but only if the above method does not work, because a new constraint would involve quite a lot of work.


Hello Liviu!

Thank you! I'm going to try it. First, I'll try the solution of assigning (let's say) a 95% for the constraint "max hours daily with an activity tag for a students set" (which is now hours=3, weight=100%) and add a constraint max hours=4, weight=100%. The problem is that I don't want to have min hours < 2... I'll check the results. If this doesn't work, I'll try the other solution.

Thanks a lot!

Liviu Lalescu

I think I will need to implement teacher(s)/students (set) activity tag min hours daily, not perfectly. Please let me know if you would use it.

Edit: It is a difficult decision. I'll think about it.

Other users: do you think it would be a useful constraint?

alex, could you please devise some input file(s)? Just tell me for what students and for what activity tag you need the new constraint.

Liviu Lalescu

I got a report by email from alex (Vangelis Karafillidis) about a trick to implement constraints students activity tag max hours daily (it is a bit complicated, but I think it should work):

Let's say that you have a set of activities with an activity tag (TAG) and you want to constrain it for a minimum number of hours daily (N) for a students set (SS). This set of activities occupies (with the activity tag) M hours in a week.
Create a pseudo teacher (for example TEACHER_TAG_SS). Create an set of (N) pseudo-activities for this pseudo-teacher with split = the number of days of the week, min days 1, weight=100%, duration=1. Then create another pseudo-activity for the TEACHER_TAG_SS with split=M-[Nx(number of days of the week)], min days=0, duration=1. Then, select the real activities with the activity tag and all the above pseudo-activities and go to, "a set of activities occupies max time slots from a selection", select M as the number of max time slots.

Liviu Lalescu

Update: this constraint was introduced on 30 November 2019 in FET-5.41.0. You need to enable it from the settings.