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I want to speed up 4dvar by increasing the number of processes.


Hello all!

Is there a limit to the number of processes when running 4dvar using MPI?

When I run WRF on an input file that has been assimilated with 4dvar, I can run it with 9 processes, but 4dvar can only be run with a maximum of 4 processes.

I understand that OpenMP cannot be used with 4dvar.

Best regards.
Hello all!

The program stopped progressing in the middle of a 9-process run, but was able to complete the run successfully with a 16-process run.

Best regards.

There is a limit to the number of processes for running 4dvar (at least in my experience there have been). I'm also assuming you mean when running da_wrfvar.exe. It's similar to the same issue of trying to use too many cores to run WRF. I hope that helps.