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
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_GRAPH_GET(COMM, MAXINDEX, MAXEDGES, INDEX, EDGES, IERROR)
INTEGER COMM, MAXINDEX, MAXEDGES, INDEX(*)
INTEGER EDGES(*), IERROR
Fortran 2008 Syntax
USE mpi_f08
MPI_Graph_get(comm, maxindex, maxedges, index, edges, ierror)
TYPE(MPI_Comm), INTENT(IN) :: comm
INTEGER, INTENT(IN) :: maxindex, maxedges
INTEGER, INTENT(OUT) :: index(maxindex), edges(maxedges)
INTEGER, OPTIONAL, INTENT(OUT) :: 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-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_Graphdims_get
4.1.2 Nov 24, 2021 MPI_Graph_get(3)
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