NAME

       MPI_Dist_graph_neighbors   - Returns the neighbors of the calling process in a distributed
       graph topology.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Dist_graph_neighbors(MPI_Comm comm, int maxindegree, int sources[], int sourceweights[],
                                    int maxoutdegree, int destinations[], int destweights[])

Fortran Syntax

       INCLUDE 'mpif.h'
       MPI_DIST_GRAPH_NEIGHBORS(COMM, MAXINDEGREE, SOURCES, SOURCEWEIGHTS,
               MAXOUTDEGREE, DESTINATIONS, DESTWEIGHTS, IERROR)
               INTEGER COMM, MAXINDEGREE, SOURCES(*), SOURCEWEIGHTS(*), MAXOUTDEGREE,
                       DESTINATIONS(*), DESTWEIGHTS(*), IERROR

INPUT PARAMETERS

       comm      Communicator with distributed graph topology (handle).

       maxindegree
                 Size of sources and sourceweights arrays (non-negative integer).

       maxoutdegree
                 Size of destinations and destweights arrays (non-negative integer).

OUTPUT PARAMETERS

       sources   Processes for which the calling process is a destination (array of  non-negative
                 integers).

       sourceweights
                 Weights of the edges into the calling process (array of non-negative integers).

       destinations
                 Processes  for  which  the  calling  process  is a source (array of non-negative
                 integers).

       destweights
                 Weights of  the  edges  out  of  the  calling  process  (array  of  non-negative
                 integers).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_Dist_graph_neighbors  returns  the source and destination ranks in a distributed graph
       topology for the calling process. This call will return up to maxindegree source ranks  in
       the  sources  array and up to maxoutdegree destination ranks in the destinations array. If
       weights were specified at the time of the  communicator's  creation  then  the  associated
       weights are returned in the sourceweights and  destweights arrays. If the communicator was
       created with MPI_Dist_graph_create_adjacent then the order of the values  in  sources  and
       destinations  is identical to the input that was used by the process with the same rank in
       comm_old in the creation call.

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   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_Dist_graph_neighbors_count