Manpages - MPI_Graph_neighbors_count.3

*MPI_Graph_neighbors_count * - 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)

  USE MPI
  ! or the older form: INCLUDE 'mpif.h'
  MPI_GRAPH_NEIGHBORS_COUNT(COMM, RANK, NNEIGHBORS, IERROR)
  	INTEGER	COMM, RANK, NNEIGHBORS, IERROR

  USE mpi_f08
  MPI_Graph_neighbors_count(comm, rank, nneighbors, ierror)
  	TYPE(MPI_Comm), INTENT(IN) :: comm
  	INTEGER, INTENT(IN) :: rank
  	INTEGER, INTENT(OUT) :: nneighbors
  	INTEGER, OPTIONAL, INTENT(OUT) :: 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