Channelflow 2.0

Using multiple processes

So I installed Channelflow 2.0 on my Manjaro Linux machine, with -DUSEMPI=on. I have openMPI on this machine.

Channelflow installed successfully and passed all make tests, but when I attempt to set -np0 and -np1 to anything other than 1 and 1, I get

CfMPI: number of MPI-processes < nproc0*nproc1

Which seems to indicate to me that I need to do something else in order to enable the usage of multiple processes. Can someone help with this?

It might depend on your local mpi setup. Are you running with mpirun / mpiexec?

1 Like

Hi Jake, thanks. I didn’t know I had to use mpiexec; not familiar with OpenMPI

For anyone curious, mpiexec -np number of processes simulateflow -args values worked out.

Also, I found my openmpi-default-hostfile to change the number of threads to 2x my number of cores on my machine. This made things better! Source: mpi - Change the number of cores OpenMPI can "see" - Stack Overflow