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.. _mpi_dist_graph_neighbors:
MPI_Dist_graph_neighbors
========================
.. include_body
:ref:`MPI_Dist_graph_neighbors` |mdash| Returns the neighbors of the calling
process in a distributed graph topology.
SYNTAX
------
C Syntax
^^^^^^^^
.. code-block:: c
#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
^^^^^^^^^^^^^^
.. code-block:: fortran
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
^^^^^^^^^^^^^^^^^^^
.. code-block:: fortran
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
------
.. include:: ./ERRORS.rst
.. seealso::
* :ref:`MPI_Dist_graph_neighbors_count`
|
