oracular (3) MPI_Graph_neighbors_count.openmpi.3.gz

Provided by: openmpi-doc_4.1.6-13.3ubuntu2_all bug

NAME
       MPI_Graph_neighbors_count  - Returns the number of neighbors of a node associated with a graph topology.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Graph_neighbors_count(MPI_Comm comm, int rank,
            int *nneighbors)


Fortran Syntax
       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_GRAPH_NEIGHBORS_COUNT(COMM, RANK, NNEIGHBORS, IERROR)
            INTEGER   COMM, RANK, NNEIGHBORS, IERROR


Fortran 2008 Syntax
       USE mpi_f08
       MPI_Graph_neighbors_count(comm, rank, nneighbors, ierror)
            TYPE(MPI_Comm), INTENT(IN) :: comm
            INTEGER, INTENT(IN) :: rank
            INTEGER, INTENT(OUT) :: nneighbors
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror


C++ Syntax
       #include <mpi.h>
       int Graphcomm::Get_neighbors_count(int rank) const


INPUT PARAMETERS
       comm      Communicator with graph topology (handle).

       rank      Rank of process in group of comm (integer).


OUTPUT PARAMETERS
       nneighbors
                 Number of neighbors of specified process (integer).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       MPI_Graph_neighbors_count  and  MPI_Graph_neighbors  provide  adjacency  information for a general, graph
       topology. MPI_Graph_neighbors_count returns the number of neighbors for the process signified by rank.


ERRORS
       Almost all MPI routines return an error value; C routines as  the  value  of  the  function  and  Fortran
       routines in the last argument. C++ functions do not return errors. If the default error handler is set to
       MPI::ERRORS_THROW_EXCEPTIONS, then on error the  C++  exception  mechanism  will  be  used  to  throw  an
       MPI::Exception object.

       Before  the  error  value  is  returned,  the current MPI error handler is called. By default, this error
       handler aborts the MPI job, except for I/O function  errors.  The  error  handler  may  be  changed  with
       MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values
       to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.


SEE ALSO
       MPI_Graph_neighbors