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MPI_Dist_graph_neighbors(3) man page (version 1.8.1)

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Name

MPI_Dist_graph_neighbors - Returns the neighbors of the calling process in a distributed graph topology.

Syntax

C Syntax


#include <mpi.h>
int MPI_Dist_graph_neighbors(MPI_Comm comm, int maxindegree, int sources[],
int sourceweights[],
                             int maxoutdegree, int destinations[], int
destweights[])

Fortran Syntax


INCLUDE ’mpif.h’
MPI_DIST_GRAPH_NEIGHBORS(COMM, MAXINDEGREE, SOURCES, SOURCEWEIGHTS,
        MAXOUTDEGREE, DESTINATIONS, DESTWEIGHTS, IERROR)
        INTEGER COMM, MAXINDEGREE, SOURCES(*), SOURCEWEIGHTS(*), MAXOUTDEGREE,
                DESTINATIONS(*), DESTWEIGHTS(*), IERROR

Input Parameters

comm
Communicator with distributed graph topology (handle).
maxindegree
Size of sources and sourceweights arrays (non-negative integer).
maxoutdegree
Size of destinations and destweights arrays (non-negative integer).

Output Parameters

sources
Processes for which the calling process is a destination (array of non-negative integers).
sourceweights
Weights of the edges into the calling process (array of non-negative integers).
destinations
Processes for which the calling process is a source (array of non-negative integers).
destweights
Weights of the edges out of the calling process (array of non-negative integers).
IERROR
Fortran only: Error status (integer).

Description

MPI_Dist_graph_neighbors returns the source and destination ranks in a distributed graph topology for the calling process. This call will return up to maxindegree source ranks in the sources array and up to maxoutdegree destination ranks in the destinations array. If weights were specified at the time of the communicator’s creation then the associated weights are returned in the sourceweights and destweights arrays. If the communicator was created with MPI_Dist_graph_create_adjacent then the order of the values in sources and destinations is identical to the input that was used by the process with the same rank in comm_old in the creation call.

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.

See Also

MPI_Dist_graph_neighbors_count


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