if_else

auto eve::if_else = functor<if_else_t>

inlineconstexpr

Defined in Header

#include <eve/module/core.hpp>

Callable Signatures

namespace eve
{
  template<eve::value U, eve::value V>
  constexpr auto if_else(bool mask, U t, V f) noexcept;
 
  template<eve::value M, eve::value U, eve::value V>
  constexpr auto if_else(M mask, U t, V f) noexcept;
 
  template<eve::value M, eve::generator U, eve::value V>
  constexpr auto if_else(M mask, U t, V f) noexcept;
 
  template<eve::value M, eve::value U, eve::generator V>
  constexpr auto if_else(M mask, U t, V f) noexcept;
 
  template<eve::conditional_expr C, eve::value U, eve::value V >
  constexpr auto if_else(C mask, U t, V f) noexcept;
 
  template<eve::conditional_expr C, eve::generator U, eve::value V >
  constexpr auto if_else(C mask, U t, V f) noexcept;
 
  template<eve::conditional_expr C, eve::value U, eve::generator V >
  constexpr auto if_else(C mask, U t, V f) noexcept;
}

Parameters

• mask: logical value or condition to use as mask.
• t: Value or constant to use where mask evaluates to true.
• f: Value or constant to use where mask evaluates to false.

Return value

The call if_else(mask, t, f) performs an elementwise selection between the elements of t and f according to the value of the elements of mask.

Possible optimizations

The following calls, where t and f are values, are optimized so the constant are not evaluated:

• if_else(mask, t , eve::allbits)
• if_else(mask, t , eve::one )
• if_else(mask, t , eve::mone )
• if_else(mask, t , eve::zero )
• if_else(mask, eve::allbits , f )
• if_else(mask, eve::one , f )
• if_else(mask, eve::mone , f )
• if_else(mask, eve::zero , f )

In addition, the following calls, where t and f are unsigned values, are optimized so the constant are not evaluated:

• if_else(mask, t , eve::valmax)
• if_else(mask, t , eve::valmin)
• if_else(mask, eve::valmax, f )
• if_else(mask, eve::valmin, f )

Example

// revision 0
#include <eve/module/core.hpp>
#include <iostream>
 
int main()
{
  eve::wide wf0{0.0, 1.0, 2.0, 3.0, -1.0, -2.0, -3.0, -4.0};
  eve::wide wf1{0.0, -4.0, 1.0, -1.0, 2.0, -2.0, 3.0, -3.0};
  eve::wide wf2{0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0};
  eve::wide wi0{0, 1, 2, 3, -1, -2, -3, -4};
  eve::wide wi1{0, -4, 1, -1, 2, -2, 3, -3};
  eve::wide wi2{0, 1, 2 ,3, 4, 5, 6, 7};
  eve::wide wu0{0u, 1u, 2u, 3u, 4u, 5u, 6u, 7u};
  eve::wide wu1{7u, 6u, 5u, 4u, 3u, 2u, 1u, 0u};
  eve::wide wu2{0u, 2u, 4u, 6u, 1u, 3u, 5u, 7u};
 
  std::cout << "<- wf0                    = " << wf0 << "\n";
  std::cout << "<- wf1                    = " << wf1 << "\n";
  std::cout << "<- wf2                    = " << wf2 << "\n";
  std::cout << "<- wi0                    = " << wi0 << "\n";
  std::cout << "<- wi1                    = " << wi1 << "\n";
  std::cout << "<- wi2                    = " << wi2 << "\n";
  std::cout << "<- wu0                    = " << wu0 << "\n";
  std::cout << "<- wu1                    = " << wu1 << "\n";
  std::cout << "<- wu2                    = " << wu2 << "\n";
                                          
  std::cout << "-> if_else(wf0, wf1, wf2) = " << eve::if_else(wf0, wf1, wf2) << "\n";
  std::cout << "-> if_else(wu0, wu1, wu2) = " << eve::if_else(wu0, wu1, wu2) << "\n";
  std::cout << "-> if_else(wi0, wi1, wi2) = " << eve::if_else(wi0, wi1, wi2) << "\n";
}