ceph/src/boost/libs/math/include/boost/math/complex/atan.hpp

   1 //  (C) Copyright John Maddock 2005.
   2 //  Use, modification and distribution are subject to the
   3 //  Boost Software License, Version 1.0. (See accompanying file
   4 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #ifndef BOOST_MATH_COMPLEX_ATAN_INCLUDED
   7 #define BOOST_MATH_COMPLEX_ATAN_INCLUDED
   8
   9 #ifndef BOOST_MATH_COMPLEX_DETAILS_INCLUDED
  10 #  include <boost/math/complex/details.hpp>
  11 #endif
  12 #ifndef BOOST_MATH_COMPLEX_ATANH_INCLUDED
  13 #  include <boost/math/complex/atanh.hpp>
  14 #endif
  15
  16 namespace boost{ namespace math{
  17
  18 template<class T>
  19 std::complex<T> atan(const std::complex<T>& x)
  20 {
  21    //
  22    // We're using the C99 definition here; atan(z) = -i atanh(iz):
  23    //
  24    if(x.real() == 0)
  25    {
  26       if(x.imag() == 1)
  27          return std::complex<T>(0, std::numeric_limits<T>::has_infinity ? std::numeric_limits<T>::infinity() : static_cast<T>(HUGE_VAL));
  28       if(x.imag() == -1)
  29          return std::complex<T>(0, std::numeric_limits<T>::has_infinity ? -std::numeric_limits<T>::infinity() : -static_cast<T>(HUGE_VAL));
  30    }
  31    return ::boost::math::detail::mult_minus_i(::boost::math::atanh(::boost::math::detail::mult_i(x)));
  32 }
  33
  34 } } // namespaces
  35
  36 #endif // BOOST_MATH_COMPLEX_ATAN_INCLUDED