Originally posted by: Bernardo88

Hello.

I am using CPLEX integrated in C++ through Concert.

I use cplex.getNcols() and cplex.getNintVars to get the number of variables and cplex.getNrows() to get the number of constraints.

This information is relative to the initial model.

I wanted to know how I can extract information of the model after presolve, namely the number of constraints and integer variables.

Thanks and Best Regards

Sorry, there is no way to get this information other than parsing the CPLEX log output (which should be easy).

What do you plan to do with that information?

Originally posted by: Bernardo88

Thank you for replying.

I'd associate the size of the reduced mip with the time required for solving it (excluding presolve time).

Since you are solving the model anyway and you plan to exclude presolve time (which is only available in the log) I think the best thing to do is to parse the CPLEX log output. You can install your own stream via IloCplex::setOut() and then parse the text that CPLEX sends to this stream.

An alternative would be to IloCplex::exportModel() the model to a SAV file and then write a small application in the callable library that obtains the information you are interested in.