Originally posted by: AnushKara

Hello everyone,

I am a beginner in using CPLEX optimization studio. I want to formulate a network flow problem. In my problem, a1 = (i, j) and a2 = (i, j) may be two different arcs in A, both connecting the nodes i and j in N. However, I have an excel file of 100 instances of i and j.  And now I can't define these variables so that it retrieves the values of i and j from excel and defines the above-mentioned statement of arc sets.  

tuple 
arc {

key 
int 
fromnode;

key 
int 
tonode;

}

The values of i in my excel file refer to tuple component fromnode and j to component tonode. However, I don't know how to define the set of arcs to be retrieved from excel.

I would be really grateful for the help.

Hi,

let me give you an example out of the netflow example : https://www.ibm.com/support/knowledgecenter/SSSA5P_12.8.0/ilog.odms.ide.help/OPL_Studio/usroplexamples/topics/opl_modlib_transport.html#usroplsamples.uss_opl_modlib.1016594__usroplsamples.uss_opl_modlib.1016717

in that example all data is in a .dat

Let me show you how to read that same data from an excel spreadsheet.

I added a new run configuration.

And in arcs.dat:

SheetConnection s("arcs.xlsx");

NumNodes from SheetRead(s,"nodes!A2:A2");
SupDem from SheetRead(s,"supplydemand!A2:A6");
Arcs from SheetRead(s,"arcs!A2:D10");

regards

NB:

Many how to with OPL at https://www.linkedin.com/pulse/how-opl-alex-fleischer/

Originally posted by: AnushKara

Thank you very much, this helped a lot!!