expm1

eve::expm1 = {}

inlineconstexpr

Callable object computing \(e^x-1\).

Defined in Header

#include <eve/module/math.hpp>

Callable Signatures

namespace eve
{
   template< eve::floating_value T >
   T expm1(T x) noexcept;
}

Parameters

• x: floating real
• z: complex argument.

Return value

1. Returns the elementwise exponential of the input minus one, with good accuracy, even for small values of x.
   • If the element is \(\pm0\), \(\pm0\) is returned
   • If the element is \(-\infty\), \(-1\) is returned
   • If the element is \(\infty\), \(\infty\) is returned
   • If the element is a NaN, NaN is returned
2. Returns elementwise the exponential of the input minus one, with good accuracy, even for small values of eve::abs(z).

Example

#include <eve/module/math.hpp>
#include <eve/wide.hpp>
#include <iostream>
 
using wide_ft = eve::wide<float, eve::fixed<8>>;
 
int main()
{
 
  wide_ft pf = {0.0f, -0.0f, -1.0f, 1.0f, eve::eps(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'
            << "-> expm1(pf)       = " << eve::expm1(pf) << '\n'
            ;
 
  float xf = 1.0f;
 
  std::cout << "---- scalar" << '\n'
            << "<- xf        = " << xf << '\n'
            << "-> expm1(xf) = " << eve::expm1(xf) << '\n';
  return 0;
}

Semantic Modifiers

• Masked Call

  The call eve::expm1[mask](x) provides a masked version of eve::expm1 which is equivalent to if_else (mask, expm1(x), x).

  Example

  #include <eve/module/math.hpp>
  #include <eve/wide.hpp>
  #include <iostream>
   
  using wide_ft = eve::wide<float, eve::fixed<8>>;
   
  int main()
  {
    wide_ft pf = {0.0f, -0.0f, -1.0f, 1.0f, 2.0f,
                 eve::inf(eve::as<float>()), 4.0f, eve::nan(eve::as<float>())};
   
    std::cout << "---- simd" <<  '\n'
              << "<- pf                = " << pf << '\n'
              << "-> exp2[pf > 1.0](pf) = " << eve::exp2[pf > 1.0](pf) << '\n';
    return 0;
  }