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FET Support (English) => Get Help => Topic started by: TAHIR on April 30, 2017, 05:52:13 PM

Title: particular period of specific groups
Post by: TAHIR on April 30, 2017, 05:52:13 PM
How make a timetable for one or two specific class (students groups ) at a particular time (period)  for any subject?
Title: Re: particular period of specific groups
Post by: Volker Dirr on April 30, 2017, 06:43:44 PM
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.
Title: Re: particular period of specific groups
Post by: rodolforg on April 30, 2017, 06:55:02 PM
Maybe just "Not available time" constraint?
Title: Re: particular period of specific groups
Post by: Volker Dirr on April 30, 2017, 11:09:26 PM
yes, that is the first constraint you/he should think about.
Title: Re: particular period of specific groups
Post by: TAHIR on May 01, 2017, 04:40:06 AM
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
Title: Re: particular period of specific groups
Post by: Volker Dirr on May 01, 2017, 09:22:24 AM
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
Title: Re: particular period of specific groups
Post by: TAHIR on May 01, 2017, 05:12:42 PM
lot of thanxx
Title: Re: particular period of specific groups
Post by: TAHIR on May 01, 2017, 05:27:15 PM
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.
Title: Re: particular period of specific groups
Post by: Volker Dirr on May 01, 2017, 05:46:13 PM
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.
Title: Re: particular period of specific groups
Post by: TAHIR on May 01, 2017, 06:05:40 PM
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.
Title: Re: particular period of specific groups
Post by: Volker Dirr on May 01, 2017, 06:33:04 PM
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.
Title: Re: particular period of specific groups
Post by: TAHIR on May 02, 2017, 04:34:19 PM
 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
Title: Re: particular period of specific groups
Post by: Volker Dirr on May 02, 2017, 05:43:39 PM
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.

Title: Re: particular period of specific groups
Post by: Volker Dirr on May 02, 2017, 07:22:53 PM
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.
Title: Re: particular period of specific groups
Post by: Benahmed Abdelkrim on May 03, 2017, 06:15:28 AM
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.
Title: Re: particular period of specific groups
Post by: TAHIR on May 03, 2017, 09:48:11 AM
Thanxx to all of you
Title: Re: particular period of specific groups
Post by: Volker Dirr on May 03, 2017, 03:33:02 PM
Quote from: Benahmed Abdelkrim on May 03, 2017, 06:15:28 AM
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.

yes and no. as you can see the german secondary sample set is from my old school. all students (24 classes) have got only 100% filled timetables and teachers have got max 2 gaps per week; but the timetable still solves in a few minutes. So: yes - 100% filled is of course more difficult. But: No - that doesn't mean it is to difficult. it can still be "pretty easy" (since it solve in a few minutes, i think that is easy).

By the way: There are a lot of variants how to make a dataset easier or more difficult, even without constraints! Just by a good/bad activity planning you can do it much more easy or even impossible.
Title: Re: particular period of specific groups
Post by: Volker Dirr on May 03, 2017, 03:39:40 PM
for example in many german primary schools teachers have got 0 gaps and students have got only 100% filled timetables, but the dataset is such easy, you can even do it without FET, just with pen and paper.
at my new secondary school i must admit it is more difficult. not as easy as the old one.
Title: Re: particular period of specific groups
Post by: TAHIR on May 03, 2017, 06:19:39 PM
Is FET available in form of android app??
Title: Re: particular period of specific groups
Post by: Volker Dirr on May 03, 2017, 07:10:24 PM
No. Please open new topics if you have got a new question.
You can try to compile FET under Android, since Qt also runs under Android. Plese check the readme file and the Qt documentation.
I still don't think that it is useful, because:
- screen of android devices are normally much smaller, will be difficult to read
- android devices normally don't have a keyboard, so it will be more difficult to use
- android devices are normally much slower than an x86 CPU. check recommended CPU topic.
- android devices are normally not plugged at a socket. so if you generate a timetable the battery will be empty pretty fast, will be stupid if you smartphone is empty just because of generating. will be stupid to plug the smartphobe at a socket while generating, because that mean you can carry the smartphone anymore.

android and ios are not designed for this task.
in my opinion it is like asking if someone use a Rolls Royce limousine to plow a field.
or like asking to use a tractor in a formula one race.
of course you can do it, but it will be a bit stupid to do it.

if you want to have a very cheap computer with an ARM CPU, i suggest to use a raspberry pi 3. it is very cheap and use less energy, but of course it is around 10 times slower than a modern x86 cpu. You can use FET on that computer. it works ok. see topic recommended CPU for timetabling.
see:
https://www.raspberrypi.org/products/raspberry-pi-3-model-b/
Title: Re: particular period of specific groups
Post by: TAHIR on May 06, 2017, 03:11:24 PM
Thanxx a lot to give wonderfull info abou FET

One more question sir

When a time table genreate for 5 or 6 days then activities hours are changed at each day.why?
How to create timetable in such a way , activities for days 1,2,3 and days 4,5,6 are different for only hours 1 & 2 rest of timetable remain same for whole week.?
Title: Re: particular period of specific groups
Post by: Volker Dirr on May 06, 2017, 03:38:15 PM
i fear i don't understand. maybe you are talking about "lock/unlock" but maybe you are talking about same hour constraint.
can you please ask more detaild. please explain with an example.
Title: Re: particular period of specific groups
Post by: TAHIR on May 06, 2017, 04:31:33 PM
A teacher T1 teach english to group of students C1 in first period (hour)  for whole week (full days.) .
A teacher T2 teaches english to group of students C2 in first period (hour ) for whole week (full days).
A period 3  (hour3 ) is a free period , i want to suggest this period also to teachers T1 & T2 .
For teacher T1  monday to wednesday and T2 thursday to saturday.
Title: Re: particular period of specific groups
Post by: Volker Dirr on May 06, 2017, 05:08:30 PM
Very diffuclt to answer without knowing your whole dataset and your idea of timetable.
What do you mean with "i want to suggest this period also to teachers"? Do you mean suggest a free time or should they teach at that time?
for the first you can use break constraint, a max hours constraint, a max continously constraint, a not available at 3th period constraint, .... Difficult to answer without knowing your dataset.
for the second i highly suggest to just lower the teacher max gaps constraint.

If all hours an monday to wendday are the same, you might think about using only "one" day instead of "three" days.
If you have got also different activities that day, then there are a lot of variant to do that. a prefferd time constraint, a same hour constraint, ... . But be carfull with those ideas, i migth be impossible and "different" might give you much "better" timetables (if you think that a low number of teacher gaps is good).