std::experimental::find_first_set, std::experimental::find_last_set
From cppreference.com
| Defined in header <experimental/simd>
|
||
template< class T, class Abi >
int find_first_set( const simd_mask<T, Abi>& k );
|
(1) | (parallelism TS v2) |
template< class T, class Abi >
int find_last_set( const simd_mask<T, Abi>& k );
|
(2) | (parallelism TS v2) |
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.
Parameters
| k | - | the simd_mask to apply the reduction to
|
Return value
An int in the range [0, simd_size_v<T, Abi>).
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
