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). |
nnodes |
Number of nodes in graph (integer). |
|||
nedges |
Number of edges in graph (integer). |
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IERROR |
Fortran only: Error status (integer). |
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.
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