petsc-3.5.4 2015-05-23

PetscBuildTwoSidedType

algorithm for setting up two-sided communication

Synopsis

typedef enum {
  PETSC_BUILDTWOSIDED_NOTSET = -1,
  PETSC_BUILDTWOSIDED_ALLREDUCE = 0,
  PETSC_BUILDTWOSIDED_IBARRIER = 1
  /* Updates here must be accompanied by updates in finclude/petscsys.h and the string array in mpits.c */
} PetscBuildTwoSidedType;

 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 MPI-1.

 PETSC_BUILDTWOSIDED_IBARRIER - nonblocking algorithm based on MPI_Issend and MPI_Ibarrier.

     Proved communication-optimal in Hoefler, Siebert, and Lumsdaine (2010). Requires MPI-3.

PetscBuildTwoSidedType

Synopsis

See Also