ceph/src/boost/libs/math/include/boost/math/complex/acosh.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_ACOSH_INCLUDED
   7 #define BOOST_MATH_COMPLEX_ACOSH_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/acos.hpp>
  14 #endif
  15
  16 namespace boost{ namespace math{
  17
  18 template<class T>
  19 inline std::complex<T> acosh(const std::complex<T>& z)
  20 {
  21    //
  22    // We use the relation acosh(z) = +-i acos(z)
  23    // Choosing the sign of multiplier to give real(acosh(z)) >= 0
  24    // as well as compatibility with C99.
  25    //
  26    std::complex<T> result = boost::math::acos(z);
  27    if(!(boost::math::isnan)(result.imag()) && signbit(result.imag()))
  28       return detail::mult_i(result);
  29    return detail::mult_minus_i(result);
  30 }
  31
  32 } } // namespaces
  33
  34 #endif // BOOST_MATH_COMPLEX_ACOSH_INCLUDED