MPI_Graph_neighbors_count
Returns the number of neighbors of a node associated with a graph topology
Synopsis
#include "mpi.h"
int MPI_Graph_neighbors_count ( comm, rank, nneighbors )
MPI_Comm comm;
int rank;
int *nneighbors;
Input Parameters
 comm  communicator with graph topology (handle)

 rank  rank of process in group of comm (integer)

Output Parameter
 nneighbors
 number of neighbors of specified process (integer)
Notes for Fortran
All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK)
havean additional argument ierr at the end of the argument list.
ierris an integer and has the same meaning as the return value of the
routinein C. In Fortran, MPI routines are subroutines, and are invoked with
thecall statement.
All MPI objects (e.g., MPI_Datatype, MPI_Comm) are of type
INTEGERin Fortran.
Errors
All MPI routines (except MPI_Wtime and MPI_Wtick) return an error value;
C routines as the value of the function and Fortran routines in the
lastargument. Before the value is returned, the current MPI error handler
iscalled. By default, this error handler aborts the MPI job. The error
handlermay be changed with MPI_Errhandler_set; the predefined error
handlerMPI_ERRORS_RETURN may be used to cause error values to be returned.
Note that MPI does not guarentee that an MPI program can continue
pastan error.
 MPI_SUCCESS
 No error; MPI routine completed successfully.
 MPI_ERR_TOPOLOGY
 Invalid topology. Either there is no topology
associated with this communicator, or it is not the correct type (e.g.,
MPI_CART when expecting MPI_GRAPH).
 MPI_ERR_COMM
 Invalid communicator. A common error is to use a null
communicator in a call (not even allowed in MPI_Comm_rank).
 MPI_ERR_ARG
 Invalid argument. Some argument is invalid and is not
identified by a specific error class (e.g., MPI_ERR_RANK).
 MPI_ERR_RANK
 Invalid source or destination rank. Ranks must be between
zero and the size of the communicator minus one; ranks in a receive
(MPI_Recv, MPI_Irecv, MPI_Sendrecv, etc.) may also be MPI_ANY_SOURCE.
Location:graphnbrcnt.c