Reply To: multi-block approach
This basically means that the GPU-only mode is useless for my application. The multi-GPU approach via MPI is then to be aimed for only.
It depends: If you want to distribute the simulation over multiple GPUs then yes, GPU-mode without parallel mode MPI can’t be used. However if you have e.g. a workstation with a single GPU you can still use multiple blocks (simply set the block count in the cuboid decomposition as normally) without requiring MPI.
As OpenLB applications that are compiled both with GPU support and parallel mode MPI can also be executed as a single process on a single GPU there is nothing lost by always including MPI and GPU support.
I’ll check the results for cylinder3d on a my systems to confirm that the statistics are calculated correctly there and come back to you.