On Wed 22. Apr 2020 at 07:11, Marius Buerkle <mbuer...@web.de> wrote:
> Hi, > > What is PetscObjectGetComm expected to return? As Patrick said, it returns the communicator associated with the petsc object. I thought it would give the MPI communicator the object lives on. So if I > create A matrix on PETSC_COMM_WORLD a call of PetscObjectGetComm for A it > would return PETSC_COMM_WORLD? But it seems to return something else, and > while most of the nodes return a similar communicator some are giving a > different one. How are you actually comparing the communicators (send code snippet)? Which MPI implementation are you using? And when are comparing comms is the comparison code written in C it FORTRAN? That said, is there a way to get the MPI communicator a matrix lives on? You are using the correct function. There is a macro as well but it’s best to use the function. Thanks, Dave > > Best, > Marius >
