cub::ReduceBySegmentOp

Defined in cub/thread/thread_operators.cuh

template<typename ReductionOpT>
struct ReduceBySegmentOp

Reduce-by-segment functor.

Given two cub::KeyValuePair inputs a and b and a binary associative combining operator f(const T &x, const T &y), an instance of this functor returns a cub::KeyValuePair whose key field is a.key + b.key, and whose value field is either b.value if b.key is non-zero, or f(a.value, b.value) otherwise.

ReduceBySegmentOp is an associative, non-commutative binary combining operator for input sequences of cub::KeyValuePair pairings. Such sequences are typically used to represent a segmented set of values to be reduced and a corresponding set of {0,1}-valued integer “head flags” demarcating the first value of each segment.

Template Parameters

ReductionOpT – Binary reduction operator to apply to values

Public Functions

inline ReduceBySegmentOp()

Constructor.

inline ReduceBySegmentOp(ReductionOpT op)

Constructor.

template<typename KeyValuePairT>
inline KeyValuePairT operator()(const KeyValuePairT &first, const KeyValuePairT &second)

Scan operator.

Template Parameters

KeyValuePairT – KeyValuePair pairing of T (value) and OffsetT (head flag)

Parameters

• first – [in] First partial reduction

• second – [in] Second partial reduction

Public Members

ReductionOpT op

Wrapped reduction operator.