17.2.87. MPI_Dist_graph_neighbors_count

MPI_Dist_graph_neighbors_count - Returns the number of in and out edges for the calling processes in a distributed graph topology and a flag indicating whether the distributed graph is weighted.

17.2.87.1. SYNTAX

17.2.87.1.1. C Syntax

#include <mpi.h>

int MPI_Dist_graph_neighbors_count(MPI_Comm comm, int *indegree,
     int *outdegree, int *weighted)

17.2.87.1.2. Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_DIST_GRAPH_NEIGHBORS_COUNT(COMM, INDEGREE, OUTDEGREE, WEIGHTED, IERROR)
     INTEGER COMM, INDEGREE, OUTDEGREE, IERROR
        LOGICAL WEIGHTED

17.2.87.1.3. Fortran 2008 Syntax

USE mpi_f08
MPI_Dist_graph_neighbors_count(comm, indegree, outdegree, weighted, ierror)
     TYPE(MPI_Comm), INTENT(IN) :: comm
     INTEGER, INTENT(IN) :: indegree, outdegree
     INTEGER, INTENT(OUT) :: weighted
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

17.2.87.2. INPUT PARAMETERS

  • comm: Communicator with distributed graph topology (handle).

17.2.87.3. OUTPUT PARAMETERS

  • indegree: Number of edges into this process (non-negative integer).

  • outdegree: Number of edges out of this process (non-negative integer).

  • weighted: False if MPI_UNWEIGHTED was supplied during creation, true otherwise (logical).

  • IERROR: Fortran only: Error status (integer).

17.2.87.4. DESCRIPTION

MPI_Dist_graph_neighbors_count and MPI_Graph_neighbors provide adjacency information for a distributed graph topology. MPI_Dist_graph_neighbors_count returns the number of sources and destinations for the calling process.

17.2.87.5. ERRORS

Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.

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.