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MPI_Dist_graph_neighbors

:ref:`MPI_Dist_graph_neighbors` |mdash| 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

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_DIST_GRAPH_NEIGHBORS(COMM, MAXINDEGREE, SOURCES, SOURCEWEIGHTS,
        MAXOUTDEGREE, DESTINATIONS, DESTWEIGHTS, IERROR)
        INTEGER COMM, MAXINDEGREE, SOURCES(*), SOURCEWEIGHTS(*), MAXOUTDEGREE,
                DESTINATIONS(*), DESTWEIGHTS(*), IERROR

Fortran 2008 Syntax

USE mpi_f08
MPI_Dist_Graph_neighbors(comm, maxindegree, sources, sourceweights,
             maxoutdegree, destinations, destweights, ierror)
     TYPE(MPI_Comm), INTENT(IN) :: comm
     INTEGER, INTENT(IN) :: maxindegree, maxoutdegree
     INTEGER, INTENT(OUT) :: sources(maxindegree), destinations(maxoutdegree)
     INTEGER :: sourceweights(*), destweights(*)
     INTEGER, OPTIONAL, INTENT(OUT) :: 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

:ref:`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 :ref:`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

.. seealso::
   * :ref:`MPI_Dist_graph_neighbors_count`