Chris@16: //  (C) Copyright John Maddock 2005.
Chris@16: //  Use, modification and distribution are subject to the
Chris@16: //  Boost Software License, Version 1.0. (See accompanying file
Chris@16: //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_MATH_COMPLEX_ATAN_INCLUDED
Chris@16: #define BOOST_MATH_COMPLEX_ATAN_INCLUDED
Chris@16: 
Chris@16: #ifndef BOOST_MATH_COMPLEX_DETAILS_INCLUDED
Chris@16: #  include <boost/math/complex/details.hpp>
Chris@16: #endif
Chris@16: #ifndef BOOST_MATH_COMPLEX_ATANH_INCLUDED
Chris@16: #  include <boost/math/complex/atanh.hpp>
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost{ namespace math{
Chris@16: 
Chris@16: template<class T> 
Chris@16: std::complex<T> atan(const std::complex<T>& x)
Chris@16: {
Chris@16:    //
Chris@16:    // We're using the C99 definition here; atan(z) = -i atanh(iz):
Chris@16:    //
Chris@16:    if(x.real() == 0)
Chris@16:    {
Chris@16:       if(x.imag() == 1)
Chris@16:          return std::complex<T>(0, std::numeric_limits<T>::has_infinity ? std::numeric_limits<T>::infinity() : static_cast<T>(HUGE_VAL));
Chris@16:       if(x.imag() == -1)
Chris@16:          return std::complex<T>(0, std::numeric_limits<T>::has_infinity ? -std::numeric_limits<T>::infinity() : -static_cast<T>(HUGE_VAL));
Chris@16:    }
Chris@16:    return ::boost::math::detail::mult_minus_i(::boost::math::atanh(::boost::math::detail::mult_i(x)));
Chris@16: }
Chris@16: 
Chris@16: } } // namespaces
Chris@16: 
Chris@16: #endif // BOOST_MATH_COMPLEX_ATAN_INCLUDED