PetscBuildTwoSidedType#
algorithm for setting up two-sided communication for use with PetscSF
Synopsis#
typedef enum {
  PETSC_BUILDTWOSIDED_NOTSET     = -1,
  PETSC_BUILDTWOSIDED_ALLREDUCE  = 0,
  PETSC_BUILDTWOSIDED_IBARRIER   = 1,
  PETSC_BUILDTWOSIDED_REDSCATTER = 2
  /* Updates here must be accompanied by updates in finclude/petscsys.h and the string array in mpits.c */
} PetscBuildTwoSidedType;
Values#
- PETSC_BUILDTWOSIDED_ALLREDUCE- classical algorithm using an- MPI_Allreduce()with a buffer of length equal to the communicator size. Not memory-scalable due to the large reduction size. Requires only an MPI-1 implementation.
- PETSC_BUILDTWOSIDED_IBARRIER- nonblocking algorithm based on- MPI_Issend()and- MPI_Ibarrier(). Proved communication-optimal in Hoefler, Siebert, and Lumsdaine (2010). Requires an MPI-3 implementation.
- PETSC_BUILDTWOSIDED_REDSCATTER- similar to above, but use more optimized function that only communicates the part of the reduction that is necessary. Requires an MPI-2 implementation.
See Also#
PetscCommBuildTwoSided(), PetscCommBuildTwoSidedSetType(), PetscCommBuildTwoSidedGetType()
Level#
developer
Location#
Index of all Sys routines
Table of Contents for all manual pages
Index of all manual pages