We are running a timetable of 5 days and I want each teacher to have one period (hour) "free" per day. This is easy to implement, but there is one day (a Friday), where we have one less period.
Monday - Thursday 8 periods
Friday - 7 periods
If I implement max 7 hours per day, then some teachers end up not having a free period on a Friday. Is there a way around it?
Thank you,
Adele
For each teacher, for Friday, a constraint activities (all activities of that teacher) occupy max 6 time slots from selection (selection with X - red = all 7 slots of Friday). This is a magic constraint :)
Or another magic constraint is teachers max hours daily in interval. You might think of it (but I am not sure it might work in your exact situation). I am thinking of allowing max 6 hours in the first 7 for each day, but it might constrain too much Monday-Thursday.
Well, in fact you are wrong.
If you set max 7 hours per day, then it might happen that a teacher always have got free the last period on Monday to Thursday also. So the only difference between that 4 days and Friday is, that the free period on Friday will be 100% the last one, while on the other days the chance is below 100%. I don't know your dataset, but if the students don't have got Monday to Thursday always 8 hours per day (and I guess that is not the case), then the chance for a teacher to have free the last period on Monday to Thursday is very high! Probably close to 95%!
You can force to have a free period on Friday on several ways. There are a few variants for it. But please rethink about the problem I wrote above first. In my opinion you shouldn't add such a rule, it sounds like you only want to force teachers to stay in school, even most of the time they have nothing to do in their gap time.
Quote from: Volker Dirr on January 10, 2025, 05:54:35 PMWell, in fact you are wrong.
If you set max 7 hours per day, then it might happen that a teacher always have got free the last period on Monday to Thursday also. So the only difference between that 4 days and Friday is, that the free period on Friday will be 100% the last one, while on the other days the chance is below 100%. I don't know your dataset, but if the students don't have got Monday to Thursday always 8 hours per day (and I guess that is not the case), then the chance for a teacher to have free the last period on Monday to Thursday is very high! Probably close to 95%!
You can force to have a free period on Friday on several ways. There are a few variants for it. But please rethink about the problem I wrote above first. In my opinion you shouldn't add such a rule, it sounds like you only want to force teachers to stay in school, even most of the time they have nothing to do in their gap time.
In our setting teachers are always at school, irrespective of whether they have class or not. I am trying to be "nice" to ensure they have a "gap" on a Friday somehwere, in other words, not working every lesson there is. And yes, they will have the last lesson "free", but by that time they're home already. I just want them to be able to have one admin period during the day at school.
So in your school, all the teachers that have free on Monday to Thursday in the last period must stay in the school even there is nothing to do for them?
Just interested in your data set: How many teachers have got free on Monday to Thursday in the last hour?
Adele, if I understand correctly your problem, you need to ensure that each one of the teachers will have one free hour (gap), which should be placed between their activities. I.e. you need each one of the teachers to have at least one activity before this free period (gap) and at least one activity after this free period (gap). And you need it for all the days of the week. Right? In this case, I am afraid that you might need to use some specialized tricks... So, please confirm first if the above description of your problem is correct.
Vangelis.
Yes, Vangelis, I guess that might be a variant that she is thinking about. Even in that case I think it is a bad idea (except all teachers are work full time). But as soon as there is at least one half time working teacher at the school, you will notice that this "rule" doesn't make sense.
I guess most guys want to "solve" the "substitution problem" by such rules. But in that case, if you think closer, you will always have problems with the 1st and last hour if the gaps are only in between.
If you want to care about the "substitution problem", in my opinion the best variant is generating one (or, if your school is larger, more) a "fake room(s)" and place an "empty" activity with one teacher in the pseudo room. So you will always have a teacher that can do the substitution. I know several schools that do it that way and they like it, since they know when they must do the substitution.
The problem with that solution is that in fact it increases the number of gaps by purpose indirectly. That is why this kind of timetabling is not allowed in some countries, except you ALWAYS pay that hours (so you need to pay them, even if you didn't needed a teacher to do the substitution.
That is why we don't do it that way. Since we have pretty many half time teachers at school, we can reduce the number of gaps as much as possible and we always still have got enough teachers that can do the substitution. I know that this might be a problem at school with only full time working teachers, but i recommend to check it with your data set even if you think in theory there might be a problem. The mind of a human is sadly not able to "see" the correct solution - so try and check it. (If your mind is able to "see" it, then in fact you don't need a timetabling tool like FET, since in that case you are clever enough to just write the timetable with Word or Excel in 1 minute per teacher. So you will be able to do the timetable of your school with pen & paper only in a few minutes. That is for example possible at many primary schools with many full time working teachers. In that case it is often possible very very easy.
Thank you for your replies Vangelis and Volker
Volker, I'm not trying to solve a substitution problem, I just want an "admin" period for a teacher per day and decided that the best way was to actually create 5 admin periods with minimum 1 day between activities and added no students to the activity. In that way, it ensured each teacher had an admin/free/gap lesson.
After the timetable generated, I just opened the generated FET file, which contains the "Admin" periods and removed them, leaving a gap every day.
Thanks again for your reply.
If you set the "admin" with subject "---", then you don't need to delete them later, because it looks like they are empty.
I am a teacher myself over 25 years now. What should a teacher do in a daily admin period? The most days of a week there is no admin hour needed for a teacher. But on other days even 20 hours are not enough for admin only.