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MPI_Graphdims_get  - Retrieves graph topology information associated
with a communicator. 
 
 #include <mpi.h>
int MPI_Graphdims_get(MPI_Comm comm, int *nnodes, int *nedges)
 
 USE MPI
! or the older form: INCLUDE ’mpif.h’
MPI_GRAPHDIMS_GET(COMM, NNODES, NEDGES, IERROR)
    INTEGER    COMM, NNODES, NEDGES, IERROR
 
 USE mpi_f08
MPI_Graphdims_get(comm, nnodes, nedges, ierror)
    TYPE(MPI_Comm), INTENT(IN) :: comm
    INTEGER, INTENT(OUT) :: nnodes, nedges
    INTEGER, OPTIONAL, INTENT(OUT) :: ierror
 
comm Communicator for group with graph structure (handle).
  
Functions MPI_Graphdims_get and MPI_Graph_get retrieve the
graph-topology information that was associated with a communicator by MPI_Graph_create.nnodes Number of nodes in graph (integer). nedges Number
of edges in graph (integer). IERROR Fortran only: Error status (integer).
  
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.
 
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.
 
 
MPI_Graph_create 
 MPI_Graph_get
   
 
 
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