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

source code of include/boost/math/special_functions/hypot.hpp