Hi Renger
Thank you for your help. I’ll try to make the problem clear
–The problem is " Exams scheduling in an university"
–The set “i” indicate the indexes for courses ( for example for the course “Dynamic programming” i is equal to 1, for “Econometric” i = 2 and so on)
–For each course, due to the number of registered students, we may have two or more codes which ( set c ), for example if the capacity of the class for the econometric is 10 and 14 students register for the class, we have code 1 and code 2 for econometric.
– There are 3 groups of students ( based on which semester they are experiencing and j=1,2,3) For example for the first group, 3 different courses are available ( i=1,2,3) and for the second one, 4 courses are availbe ( i= 4,5,6,7) and so on
– We have a set called Ij which indicates the available courses for student group j ( for example I1= 1,2,3 as I said before )
– There is a set called Ci which indicates the available codes for course j ( for example if i=1(econometric), C1=1,2)
How can I define a set like Ci ?so in a constraint, when i=1 , Ci should return 1,2 , In other words, C(‘1’)= /1,2/
I attach the paper that I’m trying to write the model for to make the problem more clear
From: renger@vannieuwkoop.ch
To: gamsworld@googlegroups.com
Subject: RE: AW: related sets
Date: Mon, 12 Jan 2015 10:37:11 +0000
Hi Bahman
Here you can see the techniques used: “ord†as well as “sameasâ€. You might have to adjust it slightly to your needs.
Next time it would be better to send also the relevant Gams code (with the definitions of the sets and your attempts of the equation, because this would make it much easier to find an answer and test the possible solution)
Cheers
Renger
Alias(c,cc), (f,ff);
Eq19_3(f,ff,b)$(ord(f) lt ord(ff))…
sum((i,c), z(i,c,b,f)) =L= M sum((i,c), z(i,c,b,ff));
(based on your wish to have a set l that lags 1 and 2 periods with regard to t, not with regard to the equation you send).
Eq17_3(i,j)$(ord(l) >2)…
Sum((s,t)(not sameas(s,i)), x(s,j,t-2,t) =L= (1 – sum(t, x((i,j,t-1,t) * M);
\
\
\
Eq7_3(i,c,cc,b)(not sameas(c,ss) …
Sum(f, z(i,c,b,f) = sum(f, z,i,cc,b)
Cheers
Renger
From: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] On Behalf Of Bahman Alipour Shandiz
Sent: Sonntag, 11. Januar 2015 21:22
To: gamsworld@googlegroups.com
Subject: RE: AW: related sets
Thanks for your reply
This is the link of my previous question, I’ve uploaded the constraints there
https://groups.google.com/forum/#!searchin/gamsworld/bahman$20alipourr/gamsworld/f5LtplbOcR8/DGyIWEpXIJ4J
From: renger@vannieuwkoop.ch
To: gamsworld@googlegroups.com
Subject: AW: related sets
Date: Sun, 11 Jan 2015 19:25:56 +0000
Hi Bahman
Send the constraint, because it is not clear from your question how this second set is used in the constraint.
Renger
Von: gamsworld@googlegroups.com [mailto:gamsworld@googlegroups.com] Im Auftrag von Bahman Alipour
Gesendet: Sunday, January 11, 2015 03:05
An: gamsworld@googlegroups.com
Betreff: related sets
Hello,
In my model, I have a set of days which is shown by t /t1*t10/ , Also I have another set which is related to set t. I mean, in the constraints, for example when t=t1 the second set should return {1,2} , if t=t2, the second set should return {2,3} and so on.
I tried this one :
set
t /t1*t10/
rt(t1) /1,2/;
but apparently it does not work, can anybody help me please?
–
2251-712X-8-28.pdf (479 KB)