MPI_Graphdims_get(3) Open MPI MPI_Graphdims_get(3)
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
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_GRAPHDIMS_GET(COMM, NNODES, NEDGES, IERROR)
INTEGER COMM, NNODES, NEDGES, IERROR
Fortran 2008 Syntax
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
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-topol-
ogy 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++ func-
tions 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
4.1.2 Nov 24, 2021 MPI_Graphdims_get(3)
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