std::experimental::simd_abi::deduce

 

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Technical specifications

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Extensions for concurrency 2 (concurrency TS v2)

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Extensions for parallelism v2

Parallel exceptions
exception_list
Additional execution policies
execution::vector_policy	execution::unsequenced_policy
Algorithms
induction reductionreduction_plusreduction_minusreduction_multiplies	reduction_bit_andreduction_bit_orreduction_bit_xorreduction_minreduction_max	for_loopfor_loop_stridedfor_loop_nfor_loop_n_strided
execution::no_vec
execution::ordered_update_t
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define_task_blockdefine_task_block_restore_thread
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SIMD library

Main classes
simd	simd_mask
ABI tags
simd_abi::scalar simd_abi::fixed_size	simd_abi::native simd_abi::compatible	simd_abi::max_fixed_size simd_abi::deduce
Alignment tags
element_aligned_tagelement_aligned	vector_aligned_tagvector_aligned	overaligned_tagoveraligned
Where expression
where	where_expression	const_where_expression
Casts
simd_caststatic_simd_cast	to_fixed_sizeto_compatibleto_native	splitsplit_by concat
Algorithms
min max	minmax clamp
Reduction
reducehminhmax
Mask reduction
all_ofany_ofnone_ofsome_of	popcount find_first_setfind_last_set
Traits
is_simdis_simd_mask is_abi_tag is_simd_flag_type	simd_size memory_alignment rebind_simdresize_simd
Math functions

 

Defined in header <experimental/simd>
template< class T, std::size_t N, class ...Abis > struct deduce;		(parallelism TS v2)

The type deduce<T, N, Abis...>::type is present if and only if:

• T is a vectorizable type,
• simd_abi::fixed_size<N> is supported, and
• every type in Abis... is an ABI tag.

Let DA denote deduce<T, N, Abis...>::type when it presents, then

• simd_size_v<T, DA> == N,
• simd<T, DA> is default constructible, i.e. it is supported,
• DA is simd_abi::scalar if N == 1, otherwise it is implementation-defined.

Member types

Name	Definition
type	an ABI tag type suitable for specified element type T and size N

Helper types

template< class T, std::size_t N, class ...Abis > using deduce_t = typename deduce<T, N, Abis...>::type;		(parallelism TS v2)

Notes

simd_abi::deduce is SFINAE-friendly.

The ABI tag deduced via this facility is a Quality-of-Implementation feature. Implementations can base the choice on Abis..., but can also ignore the Abis... arguments. A simple implementation might simply return fixed_size<N> unconditionally. An optimized implementation might return an implementation-defined extended ABI tag for most inputs. Consequently, if you need an ABI tag for a certain number of elements, use fixed_size if ABI stability is of concern, and prefer deduce_t otherwise.

See also

scalar (parallelism TS v2)	tag type for storing a single element (typedef)
fixed_size (parallelism TS v2)	tag type for storing specified number of elements (alias template)
compatible (parallelism TS v2)	tag type that ensures ABI compatibility (alias template)
native (parallelism TS v2)	tag type that is most efficient (alias template)