egamma

auto eve::egamma = functor<egamma_t>

inlineconstexpr

Defined in Header

#include <eve/module/math.hpp>

Callable Signatures

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

Parameters

• x : Type wrapper instance embedding the type of the constant.

Return value

The call eve::egamma(as<T>()) returns \(\gamma = \lim_{n\to\infty}\left( \sum_{k = 0}^n \frac1k - \log n\right )\).

Example

#include <eve/module/math.hpp>
#include <eve/wide.hpp>
#include <iostream>
#include <iomanip>
 
using wide_ft = eve::wide<float>;
 
template<typename T>
consteval auto constexpr_egamma() { return eve::egamma(eve::as<T>{}); }
 
int main()
{
  wide_ft wxf;
 
  std::cout << "---- simd"  << std::setprecision(9) << std::endl
            << "-> egamma(as<wide_ft>())       = " << eve::egamma(eve::as<wide_ft>())            << std::endl
            << "-> egamma(as(wxf))             = " << eve::egamma(eve::as(wxf))                  << std::endl;
 
  double       xf;
 
  std::cout << "---- scalar" << std::endl
            << "-> egamma(as<float>())         = " << eve::egamma(eve::as(float())) << std::endl
            << "-> egamma(as<xf))              = " << eve::egamma(eve::as(xf))      << std::endl;
 
 
  std::cout << "-> constexpr egamma            = " << constexpr_egamma<float>() << std::endl;
 
  return 0;
}