is_negative

eve::is_negative = {}

inlineconstexpr

Returns a logical true if and only if the element value is signed and has its sign bit set.

Defined in Header

#include <eve/module/core.hpp>

Callable Signatures

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

Parameters

• x : argument.

Return value

For signed types The call is_negative(x) elementwise returns true if and only if the bit of sign (most significant bit) is set.

Note

this function coincides with is_ltz on integral real values, but for floating values T, is_negative(mzero<T>) is true and if n is a Nan the result depends of the bit of sign of n which can be out of control although not undefined.

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, -1.5f, -2.0f, eve::nan(eve::as<float>()),
                eve::inf(eve::as<float>()), eve::minf(eve::as<float>()), -eve::nan(eve::as<float>())};
 
  std::cout << "---- simd" << '\n'
            << "<- pf              = " << pf << '\n'
            << "-> is_negative(pf) = " << eve::is_negative(pf) << '\n';
 
  float xf = 1.0f;
 
  std::cout << "---- scalar" << '\n'
            << "<- xf              = " << xf << '\n'
            << "-> is_negative(xf) = " << eve::is_negative(xf) << '\n';
  return 0;
}

Semantic Modifiers

• Masked Call

  The call eve;is_negative[mask](x) provides a masked version of eve::is_negative which is equivalent to if_else (mask, is_negative(x), eve::false( eve::as(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, -1.5f, -0.0f, eve::nan(eve::as<float>()),
                  eve::inf(eve::as<float>()), eve::minf(eve::as<float>()), -eve::nan(eve::as<float>())};
   
    std::cout << "---- simd" << '\n'
              << "<- pf              = " << pf << '\n'
              << "-> is_negative[pf < 2](pf) = " << eve::is_negative[pf < 2](pf) << '\n';
    return 0;
  }