Dear Johannes,
I am only just seeing this. Thanks for the message. I actually tried an alternative route which I think is ok but not entirely sure…
I have a binary variable X(l,m) for the existence of a link, l, in the Network (which, again is a 1 in the table defined).
Set
n /n1*n5/
*List of Nodes in Network
alias (n,e);
Set m /1,2/;
*Modules to which the Links (and Nodes) can be assigned.
table CM (n,n)
n1 n2 n3 n4 n5
n1 1 1
n2 1 1
n3 1
n4 1
n5 1 1
Binary Variables
X1(m), X2(m), X3(m), X4(m),X5(m), X6(m), X7(m), X8(m)
To reference the table within the constraints, I have used for example CM(‘n1’,‘n2’)*X1(m) to represent the first one in the table, where X1(m) refers to Link 1 being assigned to module ‘m’.
I was thinking there however may be a way in which I can instead say, in a loop of some sort, that for all CM(n,n)=1 (Since the matrix is sparse anyway), that the subsequent constraints would apply…
CM(‘n1’,‘n2’)*X1(m) =l=Y(n,m).
Y(n,m) is another binary variable for the assignment of nodes in the network,n, to modules, m.
In that way, I may not have to reference each link Individually from the table by stating explicitly what its location is in CM(‘n1’, ‘n2’). Further, I may not have to define a variable for each link (8 in this case) and can simply use X(l,m).
But I am not sure how to do this.
If you have an idea of what I am trying to do, your assistance will be greatly appreciated once again 
Thank you.
Regards,
Monigram
On Tuesday, July 24, 2012 10:33:05 AM UTC+1, Johannes Hedtrich wrote:
Hello,
i’m not sure i understand your problem completely, but here is my guess:
set n /n1n5/;
alias(n, n1)
set m /m1m5/;
set modules(m,n) /
m1 . n2
m1 . n5
m2 . n3
m2 . n4/;
parameter network(n, n1);
network(n,n1) = uniformint(0,1);
parameter module_links(m);
module_links(m) = sum(n$modules(m,n),sum(n1$modules(m,n1),network(n,n1)));
display network, module_links;
this hopefully goes into the direction what you’re looking for and gives you a starting point from which to start
kind regards,
johannes
Am Samstag, 21. Juli 2012 14:41:24 UTC+2 schrieb MoniGram:
Good day,
I am fairly new to GAMs. I wanted to represent a network with the connection or links between its nodes, n, represented as 1’s. Essentially, I would like the nodes to be grouped into modules (called ‘m’) as well as have the links between nodes should be grouped to modules also.
However, in my code, I would like to sum over these links that I call ‘l’ from the table CM representing the network, and there by determine the number of links (or 1’s) assigned to a module. I am not sure how to do this. Here is the table of nodes and binary variables to assign the link ‘l’ to a module.
Can anyone suggest a way to link it together?
Table CM(n,n) “Connectivity Matrix for Links between nodes n and e”
n1 n2 n3 n4 n5
n1 1 1
n2 1 1
n3 1
n4 1
n5 1 1 ;
Binary Variables
Xlm(l,m)
cons6(m)…Lm(m)=e=sum(l,Xlm(l,m));
(Lm is the total number of links assigned to a module, m).
So the problem is, I am not sure where I should reference the table name CM since ‘l’ is a set and I have been getting no value by saying
Set
l /CM/
Thanks!
–
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