Originally posted by: Nodame

I am calling Cplex from C# to solve an LP Optimization problem. The problem I have is that it takes too long for the solver to find a solution.

I am thinking that maybe my problem is too large. I would like to know how large the problem is (Number of variables and total number of constraints).

I know I can have an idea of what the problem looks like by using:

cplex.ExportModel("MYmodel.lp"); 

However, when I open the file MYModel.lp (using Notepad for instance), it seems like some of the constraints are omitted, and I don't see a way to know the exact number of variables and constraints.

My question is, is there an easy way to have these information: for instance a report that says:

Number of variables = blah

number of Constraints = blah2

Originally posted by: T_O

Hmm, I'm not an expert for all the APIs, but why not export the model as sav-file and read it into the interactive optimizer? Then dis prob stat should give you enough information.

Just out of curiosity: Is it LP or MIP?

Best regards,
Thomas

Originally posted by: Nodame

Thanks for your answer T_O. I am not sure but it is my understanding that a .sav file can be opened using SPSS software. i don't have SPSS installed on my computer. I created the 'MYModel.sav' file. When I try opening it using Visual studio, it appears there is no readable information.

How do I open this file using the 'interactive optimizer'? Is it an IBM feature that uses the OPL Language? I guess I haven't used this feature yet and I am not sure how to go about it. I am calling Cplex from C#.

My model is supposed to be a MIP .

Originally posted by: T_O

Typically, just open a command prompt in the folder where your .sav-file is. Then start CPLEX by entering cplex

In CPLEX type

r MYModel.sav
dis prob stat

Best regards,
Thomas

It may help to look at the reference documentation. The Cplex class has properties Ncols and Nrows that give the number of columns (variables) and rows (constraints) in the extracted model.