NAME¶

std::experimental::rebind_simd,std::experimental::resize_simd - std::experimental::rebind_simd,std::experimental::resize_simd

Synopsis¶

Defined in header <experimental/simd>
template< class T, class V > (1) (parallelism TS v2)
struct rebind_simd;
template< int N, class V > (2) (parallelism TS v2)
struct resize_simd;

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 > (parallelism TS v2)
using rebind_simd_t = typename rebind_simd<T, V>::type;
template< int N, class V > (parallelism TS v2)
using resize_simd_t = typename resize_simd<N, V>::type;

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¶

deduce obtains an ABI type for given element type and number of
deduce_t elements
(parallelism TS v2) (class template)