arg

auto kyosu::arg = eve::functor<arg_t>

inlineconstexpr

argument.

Header file

#include <kyosu/functions.hpp>

Callable Signatures

namespace kyosu
{
  //  regular call
  template<kyosu::concepts::cayley_dickson_like T> constexpr as_real_type_t<T> arg(T z)       noexcept;
 
  // semantic modifyers
  template<kyosu::concepts::cayley_dickson_like T> constexpr as_real_type_t<T> arg[radpi](T z) noexcept;
  template<kyosu::concepts::cayley_dickson_like T> constexpr as_real_type_t<T> arg[rad](T z)   noexcept;
}

Parameters

• z: Value to process.

Return value

• For floating value input, returns \(0\) or \(\pi\) according to the non negativity of z (arg of minus zero is \(\pi\)).
• For complex value input, returns elementwise the argument of the complex number i.e. eve::atan2[pedantic](imag(z),real(z)).
• For general cayley_dickson, returns \(\mathrm{atan2}(\mathrm{sign}(z_1)|\underline{z}|, z_0)\) where \(z_0\) is the real part of \(z\), \(z_1\) is the ipart of \(z\) and \(\underline{z}\) the pure part of \(z\).
  • The radpi option provides a result in \(\pi\) multiples.

External references

• Wolfram MathWorld: Argument
• Wikipedia: Argument

Example

#include <eve/wide.hpp>
#include <iostream>
#include <kyosu/kyosu.hpp>
 
int main()
{
 
  using wide_ft = eve::wide<float, eve::fixed<4>>;
  wide_ft ref1 = {3.0f, 2.0f, 1.0f, 0.5f};
  wide_ft imf1 = {2.0f, -1.0, -5.0, 0.0};
  wide_ft ref2 = {0.0, -1.0, 2.0, eve::nan(eve::as<double>())};
  auto zc = kyosu::complex_t<wide_ft>(ref1, imf1);
 
  std::cout << "---- simd" << std::endl
            << "<- zc                                 = " << zc << std::endl
            << "<- ref2                               = " << ref2 << std::endl
            << "-> arg(zc)                            = " << kyosu::arg(zc) << std::endl
            << "-> arg(ref2)                          = " << kyosu::arg(ref2) << std::endl
            << "-> arg[radpi](ref2)                   = " << kyosu::arg[kyosu::radpi](ref2) << std::endl
            << "-> arg(kyosu::cinf(eve::as<double>()) = " << kyosu::arg(kyosu::cinf(eve::as<double>())) << std::endl
            << "-> arg(kyosu::zero(kyosu::as(zc)))    = " << kyosu::arg(kyosu::zero(kyosu::as(zc))) << std::endl
            << "-> arg(kyosu::mzero(kyosu::as(zc)))   = " << kyosu::arg(kyosu::mzero(kyosu::as(zc))) << std::endl;
  return 0;
}