(let's keep users@lists.open-mpi.org in the CC list so that others can reply, too)
I don't know exactly how conda installs / re-installs mpi4py -- e.g., I don't know which MPI implementation it compiles and links against. You can check to see which MPI implementation mpiexec uses -- for Open MPI, you should be able to run "mpiexec --version" and it should have "Open MPI" somewhere in the output. I suspect MPICH's mpiexec will show something else (at a bare minimum, it won't have "Open MPI" in the output). After that, you might look to see if the conda package documentation describes which MPI implementation it uses, and/or if it has instructions about choosing which one it uses. I'm afraid I don't have much more detail here; we don't have much control on how the downstream packages bundle up Open MPI and/or use it. ________________________________ From: caitlin lamirez <caitlin.lami...@yahoo.com> Sent: Wednesday, October 25, 2023 1:17 PM To: Jeff Squyres (jsquyres) <jsquy...@cisco.com> Subject: Re: [OMPI users] MPI4Py Only Using Rank 0 Hi Jeff, After getting that error, I did reinstall MPI4py using conda remove mpi4py and conda install mpi4py. However, I am still getting the same error. If I did happen to accidentally switch to a different MPI implementation, what should I do to fix this? Thank you, Caitlin On Wednesday, October 25, 2023 at 12:05:15 PM CDT, Jeff Squyres (jsquyres) <jsquy...@cisco.com> wrote: This usually means that you have accidentally switched to using a different MPI implementation under the covers somehow. E.g., did you somehow accidentally start using mpiexec from MPICH instead of Open MPI? Or did MPI4Py somehow get upgraded or otherwise re-build itself for MPICH, but you're still using the mpiexec from Open MPI? Stuff like that. ________________________________ From: users <users-boun...@lists.open-mpi.org> on behalf of caitlin lamirez via users <users@lists.open-mpi.org> Sent: Wednesday, October 25, 2023 11:57 AM To: users@lists.open-mpi.org <users@lists.open-mpi.org> Cc: caitlin lamirez <caitlin.lami...@yahoo.com> Subject: [OMPI users] MPI4Py Only Using Rank 0 Hello, I am having a problem with MPI4Py (version: mpiexec (OpenRTE) 4.1.5). I have been using it for months without a problem, however, out of no where, I am getting a bug where my program is only using Rank 0. For example, when I run the command: mpiexec -n 5 python -m mpi4py.bench helloworld I get the following output: Hello, World! I am process 0 of 1 on Caitlins-MacBook-Air.local. Hello, World! I am process 0 of 1 on Caitlins-MacBook-Air.local. Hello, World! I am process 0 of 1 on Caitlins-MacBook-Air.local. Hello, World! I am process 0 of 1 on Caitlins-MacBook-Air.local. Hello, World! I am process 0 of 1 on Caitlins-MacBook-Air.local. I have not changed anything with my system. I was wondering if I can get some help on this issue? Thank you, Caitlin Lamirez
