sign

eve::sign = {}

inlineconstexpr

Computes the sign of the parameter.

Defined in Header

#include <eve/module/core.hpp>

Callable Signatures

namespace eve
{
   template< eve::value T >
   T sign(T x) noexcept;
}

Parameters

• x : argument.

Return value

• Computes elementwise the sign of x.
• For real x, the call is semantically equivalent to:
  • If x is greater than 0, 1 is returned.
  • If x is less than 0, -1 is returned.
  • If x is zero, x is returned.
• Moreover for floating real value if x is Nan, the result is Nan

value containing the elementwise sign of x if it is representable in this type.

Example

#include <eve/module/core.hpp>
#include <eve/wide.hpp>
#include <iostream>
 
using wide_ft = eve::wide<float, eve::fixed<8>>;
using wide_it = eve::wide<std::int16_t, eve::fixed<4>>;
 
int main()
{
  wide_ft pf = {-0.0f, 2.0f, -3.0f, -32768.0f,
                 0.0f, -2.0f, 3.0f, 32768.0f};
  wide_it pi = { 0, 2, -3, -32768};
 
  std::cout << "---- simd" << '\n'
            << "<- pf             = " << pf << '\n'
            << "-> sign(pf)       = " << eve::sign(pf) << '\n'
            
            << "<- pi             = " << pi << '\n'
            << "-> sign(pi)       = " << eve::sign(pi) << '\n';
 
  float        xf = -327.68f;
  std::int16_t xi = -328;
 
  std::cout << "---- scalar" << '\n'
            << "<- xf       = " << xf << '\n'
            << "-> sign(xf) = " << eve::sign(xf) << '\n'
            << "<- xi       = " << xi << '\n'
            << "-> sign(xi) = " << eve::sign(xi) << '\n';
  return 0;
}

Semantic Modifiers

• Masked Call

  The call eve;sign[mask](x) provides a masked version of eve::sign which is equivalent to if_else (mask, sign(x), x).

  Example

  #include <eve/module/core.hpp>
  #include <eve/wide.hpp>
  #include <iostream>
   
  using wide_ft = eve::wide<float, eve::fixed<8>>;
   
  int main()
  {
    wide_ft pf = {-0.0f, 1.0f, -3.0f, -32768.0f,
                   0.0f, -1.0f, 3.0f, 32768.0f};
   
    std::cout << "---- simd" << '\n'
              << "<- pf                    = " << pf << '\n'
              << "-> sign[abs(pf) < 2](pf) = " << eve::sign[eve::abs(pf) < 2](pf) << '\n';
    return 0;
  }