Originally posted by: SystemAdmin

I've got the concert: out of memory problem after solve() has been activated for sometimes. I tried to solve it with the node files according to the manual.

cplex.setParam(IloCplex::WorkMem, 10240); //10 GB out of 16GB RAM
cplex.setParam(IloCplex::NodeFileInd, 2);
cplex.setParam(IloCplex::WorkDir, "d:\\");

However, the problem is not yet solved. How can I check if cplex really writes the node files on the directory? I am implementing this on windows x64 with cplex 12.5 up to 8 threads.

Any help how to solve this problem would be quite appreciated.
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Originally posted by: SystemAdmin

An easy way to check that is to check whether CPLEX did create any directories/files in the WorkDir. Note that those files will be removed at the end of the solve(), so you need to check while the solve is still running.
CPLEX should also print a message

Began writing nodes to disk (directory %s created)

to the log (where %s is replaced by the directory to which the nodes are written).
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Originally posted by: SystemAdmin

Thanks, Daniel. Unfortunately, another problem surfaces, which is that the opl model size is too large and my program stops even before solve(), although I did not get any error message or exception from opl or concert. the program just hang. As an example of my problem size: NTotVar = 88790, NBinV=53119, Nrows=244541, Nonzeros=28804652. This is already considered a small problem. Any suggestions how to go around solving this problem, e.g, memory increase, would be quite appreciated.
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Originally posted by: SystemAdmin

You should ask that question on the OPL Forum. The OPL experts may know of ways to reduce the memory requirements.
If nothing else helps you could drop OPL and use the programming APIs directly. Depending on which API you use this will allow you to reduce the memory requirements for model building to the bare minimum.
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