std::experimental::reduce, std::experimental::hmin, std::experimental::hmax
From cppreference.com
| Defined in header <experimental/simd>
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template< class T, class Abi, class BinaryOperation = std::plus<> > T reduce( const simd<T, Abi>& v, BinaryOperation binary_op = {} ); |
(1) | (parallelism TS v2) |
template< class M, class V, class BinaryOperation > typename V::value_type reduce( const const_where_expression<M, V>& x, typename V::value_type identity_element, BinaryOperation binary_op = {} ); |
(2) | (parallelism TS v2) |
template< class M, class V > typename V::value_type reduce( const const_where_expression<M, V>& x, std::plus<> binary_op ) noexcept; |
(3) | (parallelism TS v2) |
template< class M, class V > typename V::value_type reduce( const const_where_expression<M, V>& x, std::multiplies<> binary_op ) noexcept; |
(4) | (parallelism TS v2) |
template< class M, class V > typename V::value_type reduce( const const_where_expression<M, V>& x, std::bit_and<> binary_op ) noexcept; |
(5) | (parallelism TS v2) |
template< class M, class V > typename V::value_type reduce( const const_where_expression<M, V>& x, std::bit_or<> binary_op ) noexcept; |
(6) | (parallelism TS v2) |
template< class M, class V > typename V::value_type reduce( const const_where_expression<M, V>& x, std::bit_xor<> binary_op ) noexcept; |
(7) | (parallelism TS v2) |
template< class T, class Abi > T hmin( const simd<T, Abi>& v ) noexcept; |
(8) | (parallelism TS v2) |
template< class M, class V > typename V::value_type hmin( const const_where_expression<M, V>& x ) noexcept; |
(9) | (parallelism TS v2) |
template< class T, class Abi > T hmax( const simd<T, Abi>& v ) noexcept; |
(10) | (parallelism TS v2) |
template< class M, class V > typename V::value_type hmax( const const_where_expression<M, V>& x ) noexcept; |
(11) | (parallelism TS v2) |
1) Reduces all values in
v over binary_op.2) Reduces the values in
x where the associated mask element is true over binary_op.3) Returns the sum of all values in
x where the associated mask element is true.4) Returns the product of all values in
x where the associated mask element is true.5) Returns the aggregation using bitwise-and of all values in
x where the associated mask element is true.6) Returns the aggregation using bitwise-or of all values in
x where the associated mask element is true.7) Returns the aggregation using bitwise-xor of all values in
x where the associated mask element is true.8) Reduces all values in
v over std::min.9) Reduces all values in
x where the associated mask element is true over std::min.10) Reduces all values in
v over std::max.11) Reduces all values in
x where the associated mask element is true over std::max.The behavior is non-deterministic if binary_op is not associative or not commutative.
Parameters
| v | - | the simd vector to apply the reduction to
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| x | - | the return value of a where expression to apply the reduction to
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| identity_element | - | a value that acts as identity element for binary_op; binary_op(identity_element, a) == a must hold for all finite a of type V::value_type
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| binary_op | - | binary FunctionObject that will be applied in unspecified order to arguments of type V::value_type or simd<V::value_type, A>, with unspecified ABI tag A. binary_op(v, v) must be convertible to V
|
Return value
The result of operation of the type:
1,8,10)
T2-7,9,11)
V::value_typeExample
Run this code
#include <array>
#include <cassert>
#include <cstddef>
#include <experimental/simd>
#include <functional>
#include <iostream>
#include <numeric>
namespace stdx = std::experimental;
int main()
{
using V = stdx::native_simd<double>;
alignas(stdx::memory_alignment_v<V>) std::array<V::value_type, 1024> data;
std::iota(data.begin(), data.end(), 0);
V::value_type acc{};
for (std::size_t i = 0; i < data.size(); i += V::size())
acc += stdx::reduce(V(&data[i], stdx::vector_aligned), std::plus{});
std::cout << "sum of data = " << acc << '\n';
using W = stdx::fixed_size_simd<int, 4>;
alignas(stdx::memory_alignment_v<W>) std::array<int, 4> arr{2, 5, 4, 1};
auto w = W(&arr[0], stdx::vector_aligned);
assert(stdx::hmin(w) == 1 and stdx::hmax(w) == 5);
}
Output:
sum of data = 523776
See also
(C++17) |
similar to std::accumulate, except out of order (function template) |