MPI_GRAPH_NEIGHBORS, MPI_Graph_neighbors

Purpose

Returns the neighbors of the given task.

C synopsis

#include <mpi.h>
MPI_Graph_neighbors(MPI_Comm comm,int rank,int maxneighbors,int *neighbors);

C++ synopsis

#include mpi.h
void MPI::Graphcomm::Get_neighbors(int rank, int maxneighbors,
                                   int neighbors[])
                                   const;

FORTRAN synopsis

include 'mpif.h' or use mpi
MPI_GRAPH_NEIGHBORS(MPI_COMM COMM,INTEGER RANK,INTEGER MAXNEIGHBORS,
      INTEGER NNEIGHBORS(*),INTEGER IERROR)

Parameters

comm
     is a communicator with graph topology (handle) (IN)

rank
     is the rank of a task within group of comm (integer) (IN)

maxneighbors
     is the size of array neighbors (integer) (IN)

neighbors
     is the ranks of tasks that are neighbors of the specified task (array
     of integer) (OUT)

IERROR
     is the FORTRAN return code. It is always the last argument.

Description

This subroutine retrieves the adjacency information for a particular task.

Errors

Invalid array size
     maxneighbors < 0

Invalid rank
     rank < 0 or rank > groupsize

MPI not initialized

MPI already finalized

Invalid communicator

No topology

Invalid topology type
     no graph topology associate with communicator

Related information

     MPI_GRAPH_CREATE