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

       INCLUDE 'mpif.h'
       MPI_GRAPH_NEIGHBORS_COUNT(COMM, RANK, NNEIGHBORS, IERROR)
            INTEGER   COMM, RANK, NNEIGHBORS, 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