MPI_Graph_create

MPI_Graph_create(3)                   MPI                  MPI_Graph_create(3)



NAME
       MPI_Graph_create -  Makes a new communicator to which topology
       information has been attached

SYNOPSIS
       int MPI_Graph_create(MPI_Comm comm_old, int nnodes, const int indx[],
                            const int edges[], int reorder, MPI_Comm *comm_graph)

INPUT PARAMETERS
       comm_old
              - input communicator without topology (handle)
       nnodes - number of nodes in graph (integer)
       indx   - array of integers describing node degrees (see below)
       edges  - array of integers describing graph edges (see below)
       reorder
              - ranking may be reordered (true) or not (false) (logical)


OUTPUT PARAMETERS
       comm_graph
              - communicator with graph topology added (handle)


NOTES
       Each process must provide a description of the entire graph, not just
       the neigbors of the calling process.


ALGORITHM
       We ignore the reorder info currently.


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.


ERRORS
       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 guarentee that an MPI
       program can continue past an error; however, MPI implementations will
       attempt to continue whenever possible.

       MPI_SUCCESS
              - No error; MPI routine completed successfully.
       MPI_ERR_TOPOLOGY
              - Invalid topology.  Either there is no topology associated with
              this communicator, or it is not the correct type (e.g., MPI_CART
              when expecting MPI_GRAPH ).
       MPI_ERR_COMM
              - Invalid communicator.  A common error is to use a null
              communicator in a call (not even allowed in MPI_Comm_rank ).
       MPI_ERR_ARG
              - Invalid argument.  Some argument is invalid and is not
              identified by a specific error class (e.g., MPI_ERR_RANK ).


LOCATION
       src/mpi/topo/graphcreate.c



                                   4/24/2013               MPI_Graph_create(3)