std::experimental::find_first_set, std::experimental::find_last_set
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Defined in header
<experimental/simd>
template< class T, class Abi >
int find_first_set( const simd_mask<T, Abi>& k );
(1)
(parallelism TS v2)
int find_first_set( const simd_mask<T, Abi>& k );
template< class T, class Abi >
int find_last_set( const simd_mask<T, Abi>& k );
(2)
(parallelism TS v2)
int find_last_set( const simd_mask<T, Abi>& k );
1) Returns the lowest index
i where k[i] is true.2) Returns the greatest index
i where k[i] is true.The behavior is undefined if any_of(k) is false.
[edit] Parameters
k
-
the
simd_mask to apply the reduction to
[edit] Return value
An int in the range [0, simd_size_v<T, Abi>).
[edit] Example
Run this code
#include <cstddef> #include <experimental/simd> #include <iostream> namespace stdx = std::experimental; template<typename Abi> int find(stdx::simd_mask<Abi> const& v) { if (stdx::any_of(v)) return find_first_set(v); return -1; } int main() { stdx::simd_mask<short> a{0}; a[2] = a[a.size() - 2] = 1; for (std::size_t i = 0; i < a.size(); ++i) std::cout << a[i] << ' '; std::cout << '\n'; std::cout << "find_first_set: " << stdx::find_first_set(a) << '\n'; std::cout << "find_last_set: " << stdx::find_last_set(a) << '\n'; std::cout << "find: " << find(a) << '\n'; a[2] = 0; std::cout << "find: " << find(a) << '\n'; a[a.size() - 2] = 0; std::cout << "find: " << find(a) << '\n'; }
Possible output:
0 0 1 0 0 0 1 0 find_first_set: 2 find_last_set: 6 find: 2 find: 6 find: -1