lfactorial

eve::lfactorial = functor<lfactorial_t>

inlineconstexpr

Header file

#include <eve/module/special.hpp>

Callable Signatures

namespace eve
{
   // Regular overload
   template <value T> constexpr as_wide_as_t<double,T> lfactorial(T x) noexcept; // 1
 
   // Lanes masking
   constexpr auto factorial[conditional_expr auto c](value auto n)     noexcept; // 2
   constexpr auto factorial[logical_value auto m](value auto n)        noexcept; // 2
}

Parameters

• n : integral or flint argument.

Return value

1. The value of \( \log n!\) is returned with the following considerations:
   • If the entry is an integral value, the result element type is always double to try to avoid overflow as possible.
   • If the entry is a floating point value which must be a flint, the result is of the same type as the entry.
   • If n elements are nor integer nor flint the result is undefined.
2. The operation is performed conditionnaly

External references

• Wolfram MathWorld: Erf
• Wikipedia: Error Function

Example

// revision 1
#include <eve/module/special.hpp>
#include <iostream>
 
int main()
{
  eve::wide<float> wf([](auto i, auto c)->float{ return 2*(i+c/2);});
  eve::wide wi = {93, 25, 32, 180, 1, 2, 3, 4};
  eve::wide<std::uint32_t> wu([](auto i, auto )->std::uint32_t{ return i;});
 
  std::cout << "<- wf             = " << wf << "\n";
  std::cout << "<- wi             = " << wi << "\n";
  std::cout << "<- wu             = " << wu << "\n";
 
  std::cout << "-> lfactorial(wf) = " << eve::lfactorial(wf) << "\n";
  std::cout << "-> lfactorial(wi) = " << eve::lfactorial(wi) << "\n";
  std::cout << "-> lfactorial(wu) = " << eve::lfactorial(wu) << "\n";
}