[This is preliminary documentation and is subject to change.]

Perform a parallel reduction operation that summarizes the results from the data contributed by all of the processes in a communicator. Unlike MPI_Allreduce(IntPtr, IntPtr, Int32, Int32, Int32, Int32), the results of this operation are returned only to the process whose rank is equivalent to root, i.e., the "root" process. See Reduce<(Of <(T>)>)(T, ReductionOperation<(Of <(T>)>), Int32)

Namespace:  MPI
Assembly:  MPI (in MPI.dll)
Version: 0.6.0.0 (0.6.0.0)

Syntax

C#
public static int MPI_Reduce(
	IntPtr sendbuf,
	IntPtr recvbuf,
	int count,
	int datatype,
	int op,
	int root,
	int comm
)
Visual Basic (Declaration)
Public Shared Function MPI_Reduce ( _
	sendbuf As IntPtr, _
	recvbuf As IntPtr, _
	count As Integer, _
	datatype As Integer, _
	op As Integer, _
	root As Integer, _
	comm As Integer _
) As Integer
Visual C++
public:
static int MPI_Reduce(
	IntPtr sendbuf, 
	IntPtr recvbuf, 
	int count, 
	int datatype, 
	int op, 
	int root, 
	int comm
)

Parameters

sendbuf
Type: System..::.IntPtr
Buffer containing the "outgoing" values contributed by the calling process to the reduction operation.
recvbuf
Type: System..::.IntPtr
Buffer that will receive the results of the parallel reduction. This argument is only significant at the root.
count
Type: System..::.Int32
The number of elements in sendbuf and recvbuf.
datatype
Type: System..::.Int32
The type of data in sendbuf and recvbuf.
op
Type: System..::.Int32
The MPI reduction operation to use, which may be one of the predefined reduction operations or a user-defined operation created with MPI_Op_create(IntPtr, Int32, Int32%).
root
Type: System..::.Int32
Identifies the root process (which will receive the intermediate of the reduction) by its rank in the communicator comm.
comm
Type: System..::.Int32
The communicator over which the reduction will occur.

See Also