Hello Robert,

> Note that it is still in a highly experimental state.
Yes, yet it is very appreciated.


Thank you very much for your help. It turned out, the mistake was completely on my side. mpi4py used my "native" mpicc instead of the one coming with PETSc.

Sorry for bothering you with this, instead of looking deeper into this myself. But I never used gdb before and it was quite some effort now, to make it work.


So, bottom line, if anyone with a similar error ever reads this.
Make sure that mpi4py uses the correct mpicc coming with PETSc. E.g.:

env MPICC=/path/to/mpicc pip install mpi4py

best regards,
JonnyB