It uses nonblocking point-to-point by default since that tends to perform better and is less prone to MPI implementation bugs, but you can select `-sf_type window` to try it, or use other strategies here depending on the sort of problem you're working with. #define PETSCSFBASIC "basic" #define PETSCSFNEIGHBOR "neighbor" #define PETSCSFALLGATHERV "allgatherv" #define PETSCSFALLGATHER "allgather" #define PETSCSFGATHERV "gatherv" #define PETSCSFGATHER "gather" #define PETSCSFALLTOALL "alltoall" #define PETSCSFWINDOW "window" PETSc does try to use GPU-aware MPI, though implementation bugs are present on many machines and it often requires a delicate environment arrangement. "Maeder Alexander" <[email protected]> writes:
I am a new user of PETSc
and want to know more about the underlying implementation for matrix-vector multiplication (Ax=y).
PETSc utilizes a 1D distribution and communicates only parts of the vector x utilized depending on the sparsity pattern of A.
Is the communication of x done with MPI-3 RMA and utilizes cuda-aware mpi for RMA?
Best regards,
Alexander Maeder