particular period of specific groups

[TAHIR]

How make a timetable for one or two specific class (students groups ) at a particular time (period)  for any subject?

[Volker Dirr]

Difficult to say without knowing your dataset.
You might use time constraint -> activities -> activities occupy max time slots
You might think you that i misunderstood your request since you want the opposite; but i understood correct. Please press the "help" button there and read the "help" comment. This is exactly what you requested, you only need to disallow the "opposite".

But on the other hand, even the above constraint is exactly what you requested, i don't recommend it (very high).
It is much better if you think about "Why do you want that". The answer can't be "Because they must have lessons at that time". That is not a reason. You must phrase the exact reason why they need lessons at that time. By that you will in all probability get the "real" reason. You should add that "real" reason as a constraint.

[rodolforg]

Maybe just "Not available time" constraint?

[Volker Dirr]

yes, that is the first constraint you/he should think about.

[TAHIR]

Actually i have 6 sets of  students , for example B1, B2 ,B3 , G1 , G2 , G3 and 6 hours (periods). I want to call set of students G1,G2,G3,B1  from period 1 to period 5  and  set of students B2,B3  from period 3 to period 6.
Is it possible ? if yes then how?
please help me

[Volker Dirr]

use constraint students not available.
it looks like you are a very beginner. i highly recommend to read the manual first. see:
http://www.timetabling.de/manual/FET-manual.en.html

[TAHIR]

lot of thanxx

[TAHIR]

I read FET manual guide carefully but a little problem not solved.
last question sir please help me
A group 'G'  is divided into two subgroups G1 & G2 for one period due to optional subjects.
How two teachers teach to these subgroups at same time.
say Mr.Yunis teach mathematics to G1 and Mr.Fakhar teach biology to G2 at same time.

[Volker Dirr]

just add 2 activities.
1st activity with students g1 and teacher Yunis.
2nd activity with students g2 and teacher Fakhar.

that is all.
Don't worry if they are not at the same time if you generate a timetable.
Thats is fine and ok. You can force that with a same starting time constraint, but i highly don't recommend it.
The much better variant is adding all other/missing activities to that groups (or the year). If the studnets have got a 100% filled timetable they will be automatilcy set by FET at the same time even without a same starting time constraint.
If your students set doesn't have got 100% filled timetable i also recommend to NOT use a same starting time constraint, because that is nearly never needed. It is much better to add other usefull constraints like students max gaps=0! So this will force it automaticly to be as the same time in many variants.

[TAHIR]

I already try this method adding 2 activities for both. problem is that both activities are shows at different hours(period) in timetable.
also try same starting time constraint but problem not solved, and shows not at the same time.

[Volker Dirr]

like i said:
"shows at different hours" -> that is normal. i highly suggest to do it that way until you added ALL activities, because in most cases NOT the same time is FINE, even you don't think so at the moment.

"same starting time ... not at same time" -> you must have done a bug. please attach your file and i will check it.

[TAHIR]

 If the studnets have got a 100% filled timetable they will be automatilcy set by FET at the same time even without a same starting time constraint.
If your students set doesn't have got 100% filled timetable i also recommend to NOT use a same starting time constraint, because that is nearly never needed.


What does it means? 100% filled timetable

[Volker Dirr]

100% filled = there is not free slot/hour/period left for the students.

for example: You have got 6 hours from monday to friday. So there are 5*6=30 slots.
a) if the students have got 30 activities, then there is no free slot left. the timetable is 100% filled.
b) if the students have got only 29 activities, then there is one free slot left. the timetable is not 100% filled. So most guys will give the students free at the last hour of one day (or at the first hour of one day).

so in variant a) you don't need the same starting time constraint. FET will set them automatically at the same time. (it might speed up, if you use same starting time constraint if there is only one variant. if there are more variants a same starting time will/might slow down generating)

in variant b) in fact they might not be at the same time, but in my opinion that is FINE as long as you added a min gap=0 and (maybe) a must start early constraint. Because FET will have several possibilities to solve a good timetable. For example it might set the 2 hours:
- both at the same time. For example Monday 3rd hour
- both at the same time. For example Monday last hour.
- one at Monday last hour and the other at Tuesday last hour. That is also fine! why do you want to disallow that variant? You might get much better timetables if you allow that variant.

[Volker Dirr]

an other advantage is if you have got 4 or more "split" activities:
for example students g1 with teacher T1, g1 with teacher T2, g2 with teacher T3 und g2 with teacher t4. even in a 100% filled timetable.
in first variant many guys thinka same starting time is fine/needed in that situation. but that is not true. if you add it without same starting time constrraint you will have a second possibility to set the activities! So you might get a better timetable and/or you might get the result faster.

[Benahmed Abdelkrim]

Excuse me to break your diaLog, but I think that 100% filled makes the generation slow(FET takes a lo of time to place the last activities in their time slots), unless the timetable is not very constrained.