ceph/src/boost/boost/math/special_functions/hypot.hpp

   1 //  (C) Copyright John Maddock 2005-2006.
   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_HYPOT_INCLUDED
   7 #define BOOST_MATH_HYPOT_INCLUDED
   8
   9 #ifdef _MSC_VER
  10 #pragma once
  11 #endif
  12
  13 #include <boost/math/tools/config.hpp>
  14 #include <boost/math/tools/precision.hpp>
  15 #include <boost/math/policies/error_handling.hpp>
  16 #include <boost/math/special_functions/math_fwd.hpp>
  17 #include <boost/config/no_tr1/cmath.hpp>
  18 #include <algorithm> // for swap
  19
  20 #ifdef BOOST_NO_STDC_NAMESPACE
  21 namespace std{ using ::sqrt; using ::fabs; }
  22 #endif
  23
  24 namespace boost{ namespace math{ namespace detail{
  25
  26 template <class T, class Policy>
  27 T hypot_imp(T x, T y, const Policy& pol)
  28 {
  29    //
  30    // Normalize x and y, so that both are positive and x >= y:
  31    //
  32    using std::fabs; using std::sqrt; // ADL of std names
  33
  34    x = fabs(x);
  35    y = fabs(y);
  36
  37 #ifdef BOOST_MSVC
  38 #pragma warning(push)
  39 #pragma warning(disable: 4127)
  40 #endif
  41    // special case, see C99 Annex F:
  42    if(std::numeric_limits<T>::has_infinity
  43       && ((x == std::numeric_limits<T>::infinity())
  44       || (y == std::numeric_limits<T>::infinity())))
  45       return policies::raise_overflow_error<T>("boost::math::hypot<%1%>(%1%,%1%)", 0, pol);
  46 #ifdef BOOST_MSVC
  47 #pragma warning(pop)
  48 #endif
  49
  50    if(y > x)
  51       (std::swap)(x, y);
  52
  53    if(x * tools::epsilon<T>() >= y)
  54       return x;
  55
  56    T rat = y / x;
  57    return x * sqrt(1 + rat*rat);
  58 } // template <class T> T hypot(T x, T y)
  59
  60 }
  61
  62 template <class T1, class T2>
  63 inline typename tools::promote_args<T1, T2>::type
  64    hypot(T1 x, T2 y)
  65 {
  66    typedef typename tools::promote_args<T1, T2>::type result_type;
  67    return detail::hypot_imp(
  68       static_cast<result_type>(x), static_cast<result_type>(y), policies::policy<>());
  69 }
  70
  71 template <class T1, class T2, class Policy>
  72 inline typename tools::promote_args<T1, T2>::type
  73    hypot(T1 x, T2 y, const Policy& pol)
  74 {
  75    typedef typename tools::promote_args<T1, T2>::type result_type;
  76    return detail::hypot_imp(
  77       static_cast<result_type>(x), static_cast<result_type>(y), pol);
  78 }
  79
  80 } // namespace math
  81 } // namespace boost
  82
  83 #endif // BOOST_MATH_HYPOT_INCLUDED
  84
  85
  86