MPI_Dist_graph_neighbors function - Message Passing Interface (original) (raw)

Returns the list of neighbors having edges into and out of the calling process, as well as the corresponding weights on the incoming and outgoing edges in a distributed graph topology.

Syntax

int WINAPI MPI_Dist_graph_neighbors(
  _In_ MPI_Comm              comm,
       _In_range_(>=,0)  int maxindegree,
       _Out_writes_opt int   sources[],
       _Out_writes_opt int   sourceweights[],
       _In_range_(>=,0)  int maxoutdegree,
       _Out_writes_opt int   destinations[],
       _Out_writes_opt int   destweights[]
);

Parameters

comm [in]
The handle of the communicator with the distributed graph topology.
maxindegree
Size of the sources and sourceweights arrays (non-negative integer).
sources[]
Ranks of processes in the communicator for which, the calling process is the destination in the distributed graph topology (array of non-negative integers).
sourceweights[]
Weights of the corresponding edges into the calling process (array of non-negative integers).
maxoutdegree
Size of the destinations and destweights arrays (non-negative integer).
destinations[]
Ranks of processes in the communicator for which the calling process is the source in the distributed graph topology (array of non-negative integers).
destweights[]
Weights of the corresponding edges out of the calling process (array of non-negative integers).

Return value

Returns MPI_SUCCESS on success. Otherwise, the return value is an error code.

In Fortran, the return value is stored in the IERROR parameter.

Fortran

    MPI_DIST_GRAPH_NEIGHBORS (COMM, MAXINDEGREE, SOURCES, SOURCEWEIGHTS,
    MAXOUTDEGREE, DESTINATIONS, DESTWEIGHTS, IERROR)
        INTEGER COMM, MAXINDEGREE, SOURCES (*), SOURCEWEIGHTS (*), MAXOUTDEGREE,
    DESTINATIONS (*), DESTWEIGHTS (*), IERROR

The incoming and outgoing edge count and the weight information can be obtained by calling MPI_Dist_graph_neighbors_count prior to calling this method. If maxindegree and maxoutdegree are less than the number of incoming and outgoing edges returned by MPI_Dist_graph_neighbors_count, then only the first part of the full list is returned.

The incoming and outgoing edge weights are returned only if the graph was created as a weighted distributed graph by the MPI_Dist_graph_create_adjacent or the MPI_Dist_graph_create methods and if MPI_UNWEIGHTED is not supplied as an argument in place of sourceweights or destweights.

Requirements