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Reply To: Choose between CPU and GPU

#9375
Adrian
Keymaster

Ok, so MPI is detected correctly.

What do you mean by “it still does not work”?

If you compiled with GPU support (i.e. GPU_CUDA is set in the PLATFORMS array of your config) then a simple mpirun -np $whatwever ./case will use the first GPU for all 32 processes which almost certainly is not what you want. You will need to specify the CUDA_VISIBLE_DEVICES properly to select one GPU per process (and you probably don’t have 32 GPUs in this system so you will need to reduce the number of processes accordingly, there is documentation on this e.g. in the GPU example configs).

If you just want to disable GPU usage all you need to do is not enable it – i.e. just remove the GPU_CUDA entry from PLATFORMS and recompile.