std::experimental::rebind_simd, std::experimental::resize_simd
From cppreference.com
| 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) |