MPI_Graph_neighbors_count(3)       Open MPI       MPI_Graph_neighbors_count(3)



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




1.4.1                            Jan 14, 2010     MPI_Graph_neighbors_count(3)
