NAME

       MPI_Graphdims_get  - Retrieves graph topology information associated with a communicator.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Graphdims_get(MPI_Comm comm, int *nnodes, int *nedges)

Fortran Syntax

       INCLUDE 'mpif.h'
       MPI_GRAPHDIMS_GET(COMM, NNODES, NEDGES, IERROR)
            INTEGER   COMM, NNODES, NEDGES, IERROR

C++ Syntax

       #include <mpi.h>
       void Graphcomm::Get dims(int nnodes[], int nedges[]) const

INPUT PARAMETER

       comm      Communicator for group with graph structure (handle).

OUTPUT PARAMETERS

       nnodes    Number of nodes in graph (integer).

       nedges    Number of edges in graph (integer).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       Functions MPI_Graphdims_get and MPI_Graph_get retrieve the graph-topology information that
       was associated with a communicator by MPI_Graph_create.

       The information provided by MPI_Graphdims_get can be used to dimension the  vectors  index
       and edges correctly for a call to MPI_Graph_get.

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_create
       MPI_Graph_get