87 lines
2.3 KiB
C++
87 lines
2.3 KiB
C++
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// (C) Copyright John Maddock 2005-2006.
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// Use, modification and distribution are subject to the
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// Boost Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_MATH_HYPOT_INCLUDED
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#define BOOST_MATH_HYPOT_INCLUDED
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#ifdef _MSC_VER
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#pragma once
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#endif
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#include <boost/math/tools/config.hpp>
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#include <boost/math/tools/precision.hpp>
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#include <boost/math/policies/error_handling.hpp>
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#include <boost/math/special_functions/math_fwd.hpp>
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#include <boost/config/no_tr1/cmath.hpp>
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#include <algorithm> // for swap
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#ifdef BOOST_NO_STDC_NAMESPACE
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namespace std{ using ::sqrt; using ::fabs; }
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#endif
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namespace boost{ namespace math{ namespace detail{
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template <class T, class Policy>
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T hypot_imp(T x, T y, const Policy& pol)
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{
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//
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// Normalize x and y, so that both are positive and x >= y:
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//
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using std::fabs; using std::sqrt; // ADL of std names
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x = fabs(x);
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y = fabs(y);
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#ifdef BOOST_MSVC
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#pragma warning(push)
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#pragma warning(disable: 4127)
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#endif
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// special case, see C99 Annex F:
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if(std::numeric_limits<T>::has_infinity
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&& ((x == std::numeric_limits<T>::infinity())
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|| (y == std::numeric_limits<T>::infinity())))
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return policies::raise_overflow_error<T>("boost::math::hypot<%1%>(%1%,%1%)", 0, pol);
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#ifdef BOOST_MSVC
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#pragma warning(pop)
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#endif
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if(y > x)
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(std::swap)(x, y);
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if(x * tools::epsilon<T>() >= y)
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return x;
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T rat = y / x;
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return x * sqrt(1 + rat*rat);
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} // template <class T> T hypot(T x, T y)
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}
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template <class T1, class T2>
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inline typename tools::promote_args<T1, T2>::type
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hypot(T1 x, T2 y)
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{
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typedef typename tools::promote_args<T1, T2>::type result_type;
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return detail::hypot_imp(
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static_cast<result_type>(x), static_cast<result_type>(y), policies::policy<>());
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}
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template <class T1, class T2, class Policy>
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inline typename tools::promote_args<T1, T2>::type
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hypot(T1 x, T2 y, const Policy& pol)
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{
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typedef typename tools::promote_args<T1, T2>::type result_type;
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return detail::hypot_imp(
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static_cast<result_type>(x), static_cast<result_type>(y), pol);
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}
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} // namespace math
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} // namespace boost
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#endif // BOOST_MATH_HYPOT_INCLUDED
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