std::experimental::rebind_simd, std::experimental::resize_simd
From cppreference.com
< cpp | experimental | simd
| Defined in header <experimental/simd>
|
||
| template< class T, class V > struct rebind_simd; |
(1) | (parallelism TS v2) |
| template< int N, class V > struct resize_simd; |
(2) | (parallelism TS v2) |
Creates a simd or simd_mask type with a different element type or size. The new type likely uses an ABI tag type different from V::abi_type.
1) Changes the element type to
T and keeps the size unchanged.2) Changes the size to
N and keeps the element type unchanged.Template parameters
| T | - | the new element type; an arithmetic type other than bool
|
| N | - | the new number of elements |
| V | - | a simd or simd_mask type |
Member types
| Name | Definition |
type
|
simd or simd_mask type with a different element type (1) or size (2)
|
Helper types
| template< class T, class V > using rebind_simd_t = typename rebind_simd<T, V>::type; |
(parallelism TS v2) | |
| template< int N, class V > using resize_simd_t = typename resize_simd<N, V>::type; |
(parallelism TS v2) | |
Example
Run this code
#include <experimental/simd> #include <iostream> namespace stdx = std::experimental; using floatv = stdx::native_simd<float>; // use double precision internally floatv dp(floatv x) { using doublev = stdx::rebind_simd_t<double, floatv>; return stdx::static_simd_cast<floatv>(stdx::simd_cast<doublev>(x) - 1.234); } template<class T> stdx::resize_simd_t<T::size() / 2, T> partial_reduction(T x) { auto [lo, hi] = stdx::split<stdx::resize_simd_t<T::size() / 2, T>>(x); return lo + hi; } int main() { floatv x([](auto i) { return 1.234f + std::numeric_limits<float>::epsilon() * i; }); x = dp(x); const auto y = partial_reduction(x); for (unsigned i = 0; i < y.size(); ++i) std::cout << y[i] << ' '; std::cout << '\n'; }
Possible output:
1.73569e-07 4.11987e-07
See also
| (parallelism TS v2) |
obtains an ABI type for given element type and number of elements (class template) |