Changing PETSc communicator

General Discussion
1

Hello everyone,

I would like to run PETSc on a subset of MPI_COMM_WORLD, hence I would like to create a smaller communicator and I was wondering where to add it in the source files (since It can not be modified in a script file like in a c++ code). I tried to declare it in PETSc-code.hpp before the initialization of PETSc but my code dead locked.

I’d appreciate any feedback on this problem.

2

You can define your own communicator in the .edp and pass that to the Mat constructor using the parameter communicator. See, e.g., FreeFem-sources/diffusion-cartesian-2d-PETSc.edp at develop · FreeFem/FreeFem-sources · GitHub.