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