Returns the number of neighbors of a node associated with a graph topology.
#include <mpi.h> int MPI_Graph_neighbors_count(MPI_Comm comm, int rank, int *nneighbors)
INCLUDE 'mpif.h' MPI_GRAPH_NEIGHBORS_COUNT(COMM, RANK, NNEIGHBORS, IERROR) INTEGER COMM, RANK, NNEIGHBORS, IERROR
#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).
nneighbors
Number of neighbors of specified process (integer).
IERROR
Fortran only: Error status (integer).
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.
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.
MPI_Graph_neighbors