NAME¶
MPI_Graph_neighbors_count - Returns the number of neighbors of a node
associated with a graph topology.
SYNTAX¶
C Syntax¶
#include <mpi.h>
int MPI_Graph_neighbors_count(MPI_Comm comm, int rank,
int *nneighbors)
Fortran Syntax¶
INCLUDE 'mpif.h'
MPI_GRAPH_NEIGHBORS_COUNT( COMM, RANK, NNEIGHBORS, IERROR)
INTEGER COMM, RANK, NNEIGHBORS, IERROR
C++ Syntax¶
#include <mpi.h>
int Graphcomm::Get_neighbors_count(int rank) const
- comm
- Communicator with graph topology (handle).
- rank
- Rank of process in group of comm (integer).
OUTPUT PARAMETERS¶
- nneighbors
- Number of neighbors of specified process (integer).
- IERROR
- Fortran only: Error status (integer).
DESCRIPTION¶
MPI_Graph_neighbors_count and MPI_Graph_neighbors provide adjacency information
for a general, graph topology. MPI_Graph_neighbors_count returns the number of
neighbors for the process signified by rank.
ERRORS¶
Almost all MPI routines return an error value; C routines as the value of the
function and Fortran routines in the last argument. C++ functions do not
return errors. If the default error handler is set to
MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism will
be used to throw an MPI:Exception object.
Before the error value is returned, the current MPI error handler is called. By
default, this error handler aborts the MPI job, except for I/O function
errors. The error handler may be changed with MPI_Comm_set_errhandler; the
predefined error handler MPI_ERRORS_RETURN may be used to cause error values
to be returned. Note that MPI does not guarantee that an MPI program can
continue past an error.
SEE ALSO¶
MPI_Graph_neighbors