MPI_Graph_get(3)                   Open MPI                   MPI_Graph_get(3)



NAME
       MPI_Graph_get  - Retrieves graph topology information associated with a
       communicator.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Graph_get(MPI_Comm comm, int maxindex, int maxedges,
            int *index, int *edges)


Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_GRAPH_GET(COMM, MAXINDEX, MAXEDGES, INDEX, EDGES, IERROR)
            INTEGER   COMM, MAXINDEX, MAXEDGES, INDEX(*)
            INTEGER   EDGES(*), IERROR


C++ Syntax
       #include <mpi.h>
       void Graphcomm::Get_topo(int maxindex, int maxedges,
            int index[], int edges[]) const


INPUT PARAMETERS
       comm      Communicator with graph structure (handle).

       maxindex  Length of vector index in the calling program (integer).

       maxedges  Length of vector edges in the calling program (integer).


OUTPUT PARAMETERS
       index     Array of integers containing the graph structure (for details
                 see the definition of MPI_Graph_create).

       edges     Array of integers containing the graph structure.

       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_Graphdims_get




1.4.1                            Jan 14, 2010                 MPI_Graph_get(3)
