stapl::skeletons::skeletons_impl::scan_blelloch_broadcast_pd< Op, T > Class Template Reference

Tis parametric dependency is used in the broadcast tree of Blelloch scan, in which each element applies the operation on inputs from the previous level of the tree and inputs from the reduction tree. Blelloch scan is an exclusive scan algorithm. More...

Public Member Functions
	scan_blelloch_broadcast_pd (Op op, T initial_value)
template<typename Coord , typename Visitor , typename In >
void	case_of (Coord const &skeleton_size, Coord const &coord, Visitor &visitor, In &&in_flow) const
	If coord is <i, level, ...> and skeleton_size is <n, m, p, ...> it wraps the WF with the following inputs and sends it to the visitor: if (i + 1) % 2m-level+1 == 0 then the given m_op is used: More...
template<typename Size , typename Coord , typename FlowIndex >
std::size_t	consumer_count (Size const &skeleton_size, Coord const &producer_coord, FlowIndex) const
	determines how many of the instances of this parametric dependency will be consuming from a producer with a given coordinate. This is a reverse query as compared to case_of. More...
template<typename Size , typename Coord >
std::size_t	consumer_count (Size const &, Coord const &, std::integral_constant< int, 0 >) const
Op	get_op () const
template<typename Coord >
int	get_result_id (Coord const &, Coord const &) const
template<typename Coord , typename Span >
void	configure (Coord &&, Span &&)

Public Types
using	consumer_count_filter_type = skeletons::filters::filter< 2 >
using	op_type = Op

Static Public Attributes
static constexpr std::size_t	in_port_size = 3
static constexpr std::size_t	op_arity = 2

Detailed Description

template<typename Op, typename T>
class stapl::skeletons::skeletons_impl::scan_blelloch_broadcast_pd< Op, T >

Tis parametric dependency is used in the broadcast tree of Blelloch scan, in which each element applies the operation on inputs from the previous level of the tree and inputs from the reduction tree. Blelloch scan is an exclusive scan algorithm.

Template Parameters

Op	the operation that is used in each element
T	the type of the initial value

See also

Prefix Sums and Their Applications, Guy E. Blelloch

scan_blelloch

Member Function Documentation

case_of()

template<typename Op , typename T >

template<typename Coord , typename Visitor , typename In >

void stapl::skeletons::skeletons_impl::scan_blelloch_broadcast_pd< Op, T >::case_of	(	Coord const &	skeleton_size,
		Coord const &	coord,
		Visitor &	visitor,
		In &&	in_flow
	)		const

If coord is <i, level, ...> and skeleton_size is <n, m, p, ...> it wraps the WF with the following inputs and sends it to the visitor: if (i + 1) % 2^m-level+1 == 0 then the given m_op is used:

• level == 0 ? constant(initial_value) : in<0>(i)
• in<1>[(i - 2^{m - level}, m-level-1)]

else stapl::identity is used instead of m_op

• level == 0 ? constant(initial_value) : in<0>(i + 2^m-level)

Parameters

skeleton_size	<n, m, p, ...> where each element is potentially multi-dimensional.
coord	<i, j, k, ...> where i < n, j < m, k < p
visitor	the information about WF and input is passed so that later this information can be converted to a node in the dependence graph
in_flow	a tuple of input flows to consume from

consumer_count() [1/2]

template<typename Op , typename T >

template<typename Size , typename Coord , typename FlowIndex >

std::size_t stapl::skeletons::skeletons_impl::scan_blelloch_broadcast_pd< Op, T >::consumer_count	(	Size const &	skeleton_size,
		Coord const &	producer_coord,
		FlowIndex
	)		const

determines how many of the instances of this parametric dependency will be consuming from a producer with a given coordinate. This is a reverse query as compared to case_of.

Parameters

skeleton_size	the size of this skeleton
producer_coord	the coordinate of the producer element which is providing data to this parametric dependency

Template Parameters

FlowIndex

the flow index on which this request is sent

consumer_count() [2/2]

template<typename Op , typename T >

template<typename Size , typename Coord >

std::size_t stapl::skeletons::skeletons_impl::scan_blelloch_broadcast_pd< Op, T >::consumer_count	(	Size const &	,
		Coord const &	,
		std::integral_constant< int, 0 >
	)		const

determines how many of the instances of this parametric dependency will be consuming from a producer with a given coordinate. This is a reverse query as compared to case_of.

This specialization is used when the request is only sent to the first input flow of the current skeleton.

Template Parameters

FlowIndex

the flow index to which this request is sent

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The documentation for this class was generated from the following file:

• scan_blelloch_broadcast_pd.hpp