log1p

eve::log1p = functor<log1p_t>

inlineconstexpr

Defined in Header

#include <eve/module/math.hpp>

Callable Signatures

namespace eve
{
   // Regular overload
   constexpr auto log1p(floating_value auto x)                          noexcept; // 1
 
   // Lanes masking
   constexpr auto log1p[conditional_expr auto c](floating_value auto x) noexcept; // 2
   constexpr auto log1p[logical_value auto m](floating_value auto x)    noexcept; // 2
}

Parameters

• x: floating value.
• c: Conditional expression masking the operation.
• m: Logical value masking the operation.

Return value

1. Returns the elementwise the natural logarithm of 1+x This function is more accurate than the expression log(1+x) if x is close to zero. In particular:
   • If the element is \(\pm0\), \(-\infty\) is returned.
   • If the element is \(\pm0\), \(+0\) is returned.
   • If the element is \(\infty\), \(\infty\) is returned.
   • If the element is less than -1, NaN is returned.

External references

• C++ standard reference

Example

// revision 1
#include <eve/module/math.hpp>
#include <iostream>
 
int main()
{
  eve::wide wf = {0.0f, -0.0f, -1.0f, 1.0f, 2.0f,
                  eve::inf(eve::as<float>()), eve::eps(eve::as<float>()), eve::nan(eve::as<float>())};
 
  std::cout << "<- wf                       = " << wf << "\n";
 
  std::cout << "-> log1p(wf)                = " << eve::log1p(wf) << "\n";
  std::cout << "-> log1p[ignore_last(2)](wf)= " << eve::log1p[eve::ignore_last(2)](wf) << "\n";
  std::cout << "-> log1p[wf != 2.0f](wf)    = " << eve::log1p[wf != 2.0f](wf) << "\n";
}