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std::experimental::is_simd, std::experimental::is_simd_mask

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< cpp‎ | experimental‎ | simd
 
 
Experimental
Technical Specification
Filesystem library (filesystem TS)
Library fundamentals (library fundamentals TS)
Library fundamentals 2 (library fundamentals TS v2)
Library fundamentals 3 (library fundamentals TS v3)
Extensions for parallelism (parallelism TS)
Extensions for parallelism 2 (parallelism TS v2)
Extensions for concurrency (concurrency TS)
Extensions for concurrency 2 (concurrency TS v2)
Concepts (concepts TS)
Ranges (ranges TS)
Reflection (reflection TS)
Mathematical special functions (special functions TR)
Experimental Non-TS
Pattern Matching
Linear Algebra
std::execution
Contracts
2D Graphics
 
 
 
Defined in header <experimental/simd>
template< class T >
struct is_simd;
(1) (parallelism TS v2)
template< class T >
struct is_simd_mask;
(2) (parallelism TS v2)
1) If T is a specialization of the simd class template, provides the member constant value equal true. For any other type, value is false.
2) If T is a specialization of the simd_mask class template, provides the member constant value equal true. For any other type, value is false.

Contents

[edit] Template parameters

T - a type to check

[edit] Helper variable template

template< class T >
inline constexpr bool is_simd_v = is_simd<T>::value;
(parallelism TS v2)
template< class T >
inline constexpr bool is_simd_mask_v = is_simd_mask<T>::value;
(parallelism TS v2)

Inherited from std::integral_constant

Member constants

value
[static]
true if T is a simd/simd_mask type, false otherwise
(public static member constant)

Member functions

operator bool
converts the object to bool, returns value
(public member function)
operator()
(C++14)
returns value
(public member function)

Member types

Type Definition
value_type bool
type std::integral_constant<bool, value>

[edit] Notes

is_simd_v<T> is necessary but not sufficient for testing whether T can be used as a SIMD type. For example, is_simd_v<simd<bool>> is true, even though bool is not included in the permissible vectorizable types. The missing condition is std::is_constructible_v<T>, which is false for simd<bool>.

[edit] Example

#include <experimental/simd>
#include <iostream>
#include <string_view>
 
namespace stdx = std::experimental;
 
template<typename T>
void test_simd(std::string_view type_name)
{
    std::cout << std::boolalpha
              << "Type: " << type_name << '\n'
              << "  is_simd: " << stdx::is_simd_v<T> << '\n'
              << "  is_constructible: " << std::is_constructible_v<T> << '\n';
}
 
template<typename T>
void test_simd_mask(std::string_view type_name)
{
    std::cout << std::boolalpha
              << "Type: " << type_name << '\n'
              << "  is_simd_mask: " << stdx::is_simd_mask_v<T> << '\n'
              << "  is_constructible: " << std::is_constructible_v<T> << "\n\n";
}
 
int main() 
{
    test_simd<int>("int");
    test_simd_mask<int>("int");
 
    test_simd<stdx::simd<float>>("simd<float>");
    test_simd_mask<stdx::simd_mask<float>>("simd_mask<float>");
 
    test_simd<stdx::simd<bool>>("simd<bool>");
    test_simd_mask<stdx::simd_mask<bool>>("simd_mask<bool>");
}

Output:

Type: int
  is_simd: false
  is_constructible: true
Type: int
  is_simd_mask: false
  is_constructible: true
 
Type: simd<float>
  is_simd: true
  is_constructible: true
Type: simd_mask<float>
  is_simd_mask: true
  is_constructible: true
 
Type: simd<bool>
  is_simd: true
  is_constructible: false
Type: simd_mask<bool>
  is_simd_mask: true
  is_constructible: false