I don't understand groups / subgroups

[karmacop]

I've read a few different documents about groups and sub groups and I still don't understand how to use them correctly in my case.

I've attached a cut down version of our timetable.

• Year 8 is a group of students of the same age
• The groups are sets of students that attend classes
• I thought sub groups were possible combinations of groups which could run at the same time but that is obviously wrong

This is how year 8 is split:

• There is a maths line (8MA1 - 8MA5). If a maths group runs then all the maths groups should run and no other year 8 group should run
• The year is then split in to the top and bottom of the year
• The top students are split into 3 different lines: 8A, 8B or 8CAPA1, 8CAPA2, 8CAPA3 or 8TM1, 8TM2, 8TM3
• So if 8A is running in a time slot then 8B should also run but not 8CAPA1 - 8CAPA3 or 8TM1 - 8TM3. If 8TM1 runs then the other TM classes should run but not the CAPA classes or 8A or 8B
• The bottom of year 8 is split similarly with 8M, 8R, 8U or 8CAPA4 - 8CAPA7 or 8TM4 - 8TM7

I don't understand how I'm meant to enter this information in to FET. Last year I used ConstraintActivitiesNotOverlapping to make sure these groups didn't over lap but there must be another way. What would be really useful is a student constraint that defines groups that can't overlap - that would make more sense to me.

Thanks for any help.

[Liviu Lalescu]

I spent much time to think of this problem, but it is very easy now after I found the solution:

Add years 8_top and 8_bottom.

Divide each one by 4 categories.

8_top:
First category: MA1..MA5
Second category: 8A,8B
Third category: 8CAPA1..8CAPA3
Fourth category: 8TM1..8TM3

8_bottom:
First category: MA1..MA5
Second category: 8M,8R,8U
Third category: 8CAPA4..8CAPA7
Fourth category: 8TM4..8TM7

This only cares about the groups that should NOT run at the same time. If you need to care about the groups that should run at the same time, there is another solution, which I will write in this case.

[Volker Dirr]

You forgot to tell him that the MA1...MA5 activities simply need exactly two students set. For example "8_top MA1" and "8_bottom MA1" in the same activity.

[karmacop]

Thank you so much - this makes a lot more sense now and it seems to be working as expected.

[karmacop]

Now I have a new problem - the dataset is too large. We have one year with 6 categories each with 6 or 7 groups. 7*7*6*6*6*6 = 63504 subgroups for just a single year. How do I get around that problem?

[Liviu Lalescu]

You need tricks.

A trick might be this: instead of category say 8CAPA1, 8CAPA2, 8CAPA3, consider the whole year 8_top and add an activity for it all. But this constrains the activities to be simultaneous.

Or you may make a single student = a subgroup. I hope Volker can tell you more.

[Volker Dirr]

yes, you need to use the "whole year" trick. (maybe think twice, it might be also possible to use a trick similar to the MA1...MA5 activities. So just put some students set in the same activity, but overall the line you need to have the whole year)

or you should use the "single student = a subgroup" trick. this is the best way, because in fact it isn't a "trick" it is the "perfect" way how to enter the data in your case.
but it is complicated if you can't extract the data from your school administration software.

which school administration software do you use?

you need to exctract the students structure like this:
year name, group name, students unique id (or name and birthday)

example:
"8","8MA1","Peter Miller 01.01.1999"
"8","8MA1","Kelly Smith 02.02.1999"
...
"8","8A","Peter Miller 01.01.1999"
"8","8B","Kelly Smith 02.02.1999"
...

if you use your school administration software also for printing credentials and/or official statistics, then there might be also enough information to extract the activities from that database.

[Robert C]

I would like to ask a similar question because I clearly do not understand Groups and Subgroups. Please do not laugh at our size, we are a small school; small enough (36 students) that this year I easily did the scheduling by hand. But, next year 2014-2105 the main campus plans to double our size (an added 40 students), and the next year 2015-2016 they intend to double us again with an added 150-160 students. I clearly need to get started out doing things right or in two years this will be unmanageable.

We have an IG class (apx. grade 9) of 24. Of that class eight of them are in a Intensive English class that takes them out of Business and English classes (this allows us to split the English class into a High and Low level).

IG - 24
Intensive English Track - 8
Standard English Track - 16

To make this more confusing, I have one student who goes to Intensive English for all of those class except for those which coincide with Business, in those periods he goes to Business.

Next year the current IG students will be in AS and 40 incoming students will be in IG

This years AS class has 18 students
5 of them are in Chemistry
13 of them are in Economics

Next year these students will be in A2

[Volker Dirr]

I am not sure if I uderstood 100%, but i think you can use the "split year automatically" feature.

So only add year "IG".
Split it automatically: Only one category needed with 2 items: "IE" and "SE".

Add another year "AS".
Split it automatically: Only one category needed with 2 items: "Chemistry" and "Economics".
(Maybe a second category if you still need to split by English. Do it similar as before.)

Please also read:
http://www.timetabling.de/manual/FET-manual.en.html#id_12

Give us more information this doesn't solve your problem.