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 |
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