epsilon.hpp

Go to the documentation of this file.

# /*
#  * Created by YongGyu Lee on 2020/12/08.
#  */
#
# ifndef VCCC_MATH_EPSILON_HPP
# define VCCC_MATH_EPSILON_HPP
#
# include <cmath>
# include <limits>
 
namespace vccc {
 
 
// TODO: rename this to be meant 'machine epsilon for numerical derivation'
template<typename T>
inline T epsilon() {
  static const auto e = static_cast<T>(std::cbrt(std::numeric_limits<T>::epsilon()));
  return e;
}
 
template<std::size_t i,
    typename Tuple, typename T>
constexpr inline auto
addEpsilon(Tuple vars, T epsilon)
{
  std::get<i>(vars) += std::get<i>(vars) == 0 ? epsilon : std::get<i>(vars) * epsilon;
  return vars;
}
 
 
} // namespace vccc
 
# endif // VCCC_MATH_EPSILON_HPP