MPI_DIST_GRAPH_CREATE returns a handle to a new communicator to which the distributed graph topology information is attached


int MPI_Dist_graph_create(MPI_Comm comm_old, int n, const int sources[],
                          const int degrees[], const int destinations[],
                          const int weights[], MPI_Info info, int reorder,
                          MPI_Comm *comm_dist_graph)

Input Parameters

input communicator (handle)
number of source nodes for which this process specifies edges (non-negative integer)
array containing the n source nodes for + which this process specifies edges (non-negative integer)
array specifying the number of destinations for each source node in the source node array (non-negative integer)
destination nodes for the source nodes in the source node array (non-negative integer)
weights for source to destination edges (non-negative integer)
hints on optimization and interpretation of weights (handle)
the ranks may be reordered (true) or not~(false)

Output Parameters

communicator with distributed graph topology added (handle)

Thread and Interrupt Safety

This routine is thread-safe. This means that this routine may be safely used by multiple threads without the need for any user-provided thread locks. However, the routine is not interrupt safe. Typically, this is due to the use of memory allocation routines such as malloc or other non-MPICH runtime routines that are themselves not interrupt-safe.

Notes for Fortran

All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK) have an additional argument ierr at the end of the argument list. ierr is an integer and has the same meaning as the return value of the routine in C. In Fortran, MPI routines are subroutines, and are invoked with the call statement.

All MPI objects (e.g., MPI_Datatype, MPI_Comm) are of type INTEGER in Fortran.


All MPI routines (except MPI_Wtime and MPI_Wtick) return an error value; C routines as the value of the function and Fortran routines in the last argument. Before the value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job. The error handler may be changed with MPI_Comm_set_errhandler (for communicators), MPI_File_set_errhandler (for files), and MPI_Win_set_errhandler (for RMA windows). The MPI-1 routine MPI_Errhandler_set may be used but its use is deprecated. 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; however, MPI implementations will attempt to continue whenever possible.

No error; MPI routine completed successfully.
Invalid argument. Some argument is invalid and is not identified by a specific error class (e.g., MPI_ERR_RANK).
Invalid communicator. A common error is to use a null communicator in a call (not even allowed in MPI_Comm_rank).
Invalid Info
Other error; use MPI_Error_string to get more information about this error code.