PetscSFCreate#

create a star forest communication context

Synopsis#

#include "petscsf.h" 
PetscErrorCode PetscSFCreate(MPI_Comm comm, PetscSF *sf)

Collective

Input Parameter#

comm - communicator on which the star forest will operate

Output Parameter#

sf - new star forest context

Options Database Key#

-sf_type type - value of type may be

    basic     -Use MPI persistent Isend/Irecv for communication (Default)
    window    -Use MPI-3 one-sided window for communication
    neighbor  -Use MPI-3 neighborhood collectives for communication

Note#

When one knows the communication graph is one of the predefined graph, such as MPI_Alltoall(), MPI_Allgatherv(), MPI_Gatherv(), one can create a PetscSF and then set its graph with PetscSFSetGraphWithPattern(). These special SFs are optimized and they have better performance than the general SFs.