Scan is a collective algorithm that performs partial reductions on data provided by each process in the communicator. Scan combines the values stored by each process into partial results delivered to each process. The values are combined in a user-defined way, specified via a delegate. If value(0), value(1), ..., value(N-1) are the values provided by the N processes in the communicator, the resulting value for the process with rank P will be value(0) op value(1) op ... op value(P). The processor with rank N-1 will receive the same result as if one had performed a Reduce<(Of <(T>)>)(T, ReductionOperation<(Of <(T>)>), Int32) operation with root N-1. Scan is sometimes called an "inclusive" scan, because the result returned to each process includes the contribution of that process. For an "exclusive" scan (that does not include the contribution of the calling process in its result), use ExclusiveScan<(Of <(T>)>)(T, ReductionOperation<(Of <(T>)>)).

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


public T Scan<T>(
	T value,
	ReductionOperation<T> op
Visual Basic (Declaration)
Public Function Scan(Of T) ( _
	value As T, _
	op As ReductionOperation(Of T) _
) As T
Visual C++
generic<typename T>
T Scan(
	T value, 
	ReductionOperation<T>^ op


Type: T
The value contributed by the calling process.
Type: MPI..::.ReductionOperation<(Of <(T>)>)
Operation used to combine two values from different processes.

Type Parameters

Any serializable type.

Return Value

The value value(0) op value(1) op ... op value(Rank)

See Also