Originally posted by: HughMacMullanIV

Hello CPLEX Folks:

We run CPLEX in a cluster environment, and it is often called from within R with Rcplex. There is no way to set the 'threads' parameter from within Rcplex, and while I've sent a request to Hector (:)), I would rather set this (and other parameters) globally. It's simple enough to set parameters from within CPLEX itself (set threads 1), but we can't figure out how to modify the global defaults (most desirable!) for CPLEX parameters, or how to save user-modified parameters so that they are automatically used on next run (user defaults).

The goal is to set the CPLEX default parameters so that threads = 1 (useful in a many-user cluster like we've got).

I predict I'm missing something simple here, but for the life of me can't figure out how to set CPLEX parameters permanently: either globally in the installation/cluster level, or personally at the user level.

Any advice would be appreciated!

Thanks, Hugh

Would using the CPLEXPARFILE environment variable (as described here) be sufficient? Note that this only applies to the interactive optimizer. If you access CPLEX through any of the programming APIs CPLEXPARFILE is not considered.

Originally posted by: HughMacMullanIV

Hi Daniel:

So close! That's definitely useful to help us lock in any of our users who happen to be using the interactive method. Implemented! :) If it only worked for any CPLEX call. I'm surprised that there is no way for an administrator to set default parameters.

Thanks for the thought! Hector (the Rcplex writer) is taking a look. I presume Rcplex uses the API, so it should be possible to add the threads piece ... and I'm hoping the default is ONE (1) instead of "use everything". :)

Of course I'd prefer to set this at the CPLEX level, as others use Matlab or Python to access CPLEX.

Thanks again, and any other thoughts would be appreciated.

-Hugh

There is an undocumented way of getting the same as CPLEXPARFILE for every CPLEX application.

If you want to know that then please drop me a message: daniel(dot)junglas(at)de(dot)ibm(dot)com.