Chris@16: //  (C) Copyright John Maddock 2005-2006.
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_HYPOT_INCLUDED
Chris@16: #define BOOST_MATH_HYPOT_INCLUDED
Chris@16: 
Chris@16: #ifdef _MSC_VER
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/math/tools/config.hpp>
Chris@16: #include <boost/math/tools/precision.hpp>
Chris@16: #include <boost/math/policies/error_handling.hpp>
Chris@16: #include <boost/math/special_functions/math_fwd.hpp>
Chris@16: #include <boost/config/no_tr1/cmath.hpp>
Chris@16: #include <algorithm> // for swap
Chris@16: 
Chris@16: #ifdef BOOST_NO_STDC_NAMESPACE
Chris@16: namespace std{ using ::sqrt; using ::fabs; }
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost{ namespace math{ namespace detail{
Chris@16: 
Chris@16: template <class T, class Policy>
Chris@16: T hypot_imp(T x, T y, const Policy& pol)
Chris@16: {
Chris@16:    //
Chris@16:    // Normalize x and y, so that both are positive and x >= y:
Chris@16:    //
Chris@16:    using std::fabs; using std::sqrt; // ADL of std names
Chris@16: 
Chris@16:    x = fabs(x);
Chris@16:    y = fabs(y);
Chris@16: 
Chris@16: #ifdef BOOST_MSVC
Chris@16: #pragma warning(push) 
Chris@16: #pragma warning(disable: 4127)
Chris@16: #endif
Chris@16:    // special case, see C99 Annex F:
Chris@16:    if(std::numeric_limits<T>::has_infinity
Chris@16:       && ((x == std::numeric_limits<T>::infinity())
Chris@16:       || (y == std::numeric_limits<T>::infinity())))
Chris@16:       return policies::raise_overflow_error<T>("boost::math::hypot<%1%>(%1%,%1%)", 0, pol);
Chris@16: #ifdef BOOST_MSVC
Chris@16: #pragma warning(pop)
Chris@16: #endif
Chris@16: 
Chris@16:    if(y > x)
Chris@16:       (std::swap)(x, y);
Chris@16: 
Chris@16:    if(x * tools::epsilon<T>() >= y)
Chris@16:       return x;
Chris@16: 
Chris@16:    T rat = y / x;
Chris@16:    return x * sqrt(1 + rat*rat);
Chris@16: } // template <class T> T hypot(T x, T y)
Chris@16: 
Chris@16: }
Chris@16: 
Chris@16: template <class T1, class T2>
Chris@16: inline typename tools::promote_args<T1, T2>::type 
Chris@16:    hypot(T1 x, T2 y)
Chris@16: {
Chris@16:    typedef typename tools::promote_args<T1, T2>::type result_type;
Chris@16:    return detail::hypot_imp(
Chris@16:       static_cast<result_type>(x), static_cast<result_type>(y), policies::policy<>());
Chris@16: }
Chris@16: 
Chris@16: template <class T1, class T2, class Policy>
Chris@16: inline typename tools::promote_args<T1, T2>::type 
Chris@16:    hypot(T1 x, T2 y, const Policy& pol)
Chris@16: {
Chris@16:    typedef typename tools::promote_args<T1, T2>::type result_type;
Chris@16:    return detail::hypot_imp(
Chris@16:       static_cast<result_type>(x), static_cast<result_type>(y), pol);
Chris@16: }
Chris@16: 
Chris@16: } // namespace math
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif // BOOST_MATH_HYPOT_INCLUDED
Chris@16: 
Chris@16: 
Chris@16: