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 | |
87 | |