//  (C) Copyright John Maddock 2005.

//  Use, modification and distribution are subject to the

//  Boost Software License, Version 1.0. (See accompanying file

//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_MATH_COMPLEX_ATAN_INCLUDED

#define BOOST_MATH_COMPLEX_ATAN_INCLUDED

#ifndef BOOST_MATH_COMPLEX_DETAILS_INCLUDED

#  include <boost/math/complex/details.hpp>

#endif

#ifndef BOOST_MATH_COMPLEX_ATANH_INCLUDED

#  include <boost/math/complex/atanh.hpp>

#endif

namespace boost{ namespace math{

template<class T> 

std::complex<T> atan(const std::complex<T>& x)

{

   //

   // We're using the C99 definition here; atan(z) = -i atanh(iz):

   //

   if(x.real() == 0)

   {

      if(x.imag() == 1)

         return std::complex<T>(0, std::numeric_limits<T>::has_infinity ? std::numeric_limits<T>::infinity() : static_cast<T>(HUGE_VAL));

      if(x.imag() == -1)

         return std::complex<T>(0, std::numeric_limits<T>::has_infinity ? -std::numeric_limits<T>::infinity() : -static_cast<T>(HUGE_VAL));

   }

   return ::boost::math::detail::mult_minus_i(::boost::math::atanh(::boost::math::detail::mult_i(x)));

}

} } // namespaces

#endif // BOOST_MATH_COMPLEX_ATAN_INCLUDED