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MPI_Graphdims_get(3) man page (version 5.0.0rc2)

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Name

C]MPI_Graphdims_getR] - Retrieves graph topology information associated with a communicator.

Syntax

C Syntax



C]#include <mpi.h>int MPI_Graphdims_get(MPI_Comm comm, int *nnodes, int *nedges)R]Fortran Syntax



C]USE MPI! or the older form: INCLUDE [aq]mpif.h[aq]MPI_GRAPHDIMS_GET(COMM, NNODES, NEDGES, IERROR) INTEGER COMM, NNODES, NEDGES, IERRORR]Fortran 2008 Syntax



C]USE mpi_f08MPI_Graphdims_get(comm, nnodes, nedges, ierror) TYPE(MPI_Comm), INTENT(IN) :: comm INTEGER, INTENT(OUT) :: nnodes, nedges INTEGER, OPTIONAL, INTENT(OUT) :: ierrorR]Input Parameter

[bu]
C]commR] : Communicator for group with graph structure (handle).

Output Parameters

[bu]
C]nnodesR] : Number of nodes in graph (integer).
[bu]
C]nedgesR] : Number of edges in graph (integer).
[bu]
C]IERRORR] : Fortran only: Error status (integer).

Description

Functions C]MPI_Graphdims_getR] and C]MPI_Graph_getR] retrieve the graph-topology information that was associated with a communicator by C]MPI_Graph_createR].

The information provided by C]MPI_Graphdims_getR] can be used to dimension the vectors index and edges correctly for a call to C]MPI_Graph_getR].

Errors

Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.

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 C]MPI_Comm_set_errhandlerR]; the predefined error handler C]MPI_ERRORS_RETURNR] 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

C]MPI_Graph_createR](3) C]MPI_Graph_getR](3)


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