Routines for managing communicators

Communicator Management

• Can find size of group associated with communicator:

  mpi_comm_size (comm, size, ierr)

• Can find rank of calling process in group associated with comm:

  mpi_comm_rank (comm, rank, ierr)

• Can compare communicators:

  mpi_comm_compare (comm1, comm2, result, ierr)

  Returns result as

  • MPI_IDENT if groups and contexts are identical.
  • MPI_CONGRUENT if groups have same members and ranking, but differ in context.
  • MPI_SIMILAR if groups have same members, but differ in ranking and context.
  • MPI_UNEQUAL otherwise.