1 files changed, 48 insertions, 0 deletions
diff --git a/src/third_party/boost-1.60.0/boost/math/special_functions/sqrt1pm1.hpp b/src/third_party/boost-1.60.0/boost/math/special_functions/sqrt1pm1.hpp
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index 00000000000..293a9d97b31
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+++ b/src/third_party/boost-1.60.0/boost/math/special_functions/sqrt1pm1.hpp
@@ -0,0 +1,48 @@
+//  (C) Copyright John Maddock 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_SQRT1PM1
+#define BOOST_MATH_SQRT1PM1
+
+#ifdef _MSC_VER
+#pragma once
+#endif
+
+#include <boost/math/special_functions/math_fwd.hpp>
+#include <boost/math/special_functions/log1p.hpp>
+#include <boost/math/special_functions/expm1.hpp>
+
+//
+// This algorithm computes sqrt(1+x)-1 for small x:
+//
+
+namespace boost{ namespace math{
+
+template <class T, class Policy>
+inline typename tools::promote_args<T>::type sqrt1pm1(const T& val, const Policy& pol)
+{
+   typedef typename tools::promote_args<T>::type result_type;
+   BOOST_MATH_STD_USING
+
+   if(fabs(result_type(val)) > 0.75)
+      return sqrt(1 + result_type(val)) - 1;
+   return boost::math::expm1(boost::math::log1p(val, pol) / 2, pol);
+}
+
+template <class T>
+inline typename tools::promote_args<T>::type sqrt1pm1(const T& val)
+{
+   return sqrt1pm1(val, policies::policy<>());
+}
+
+} // namespace math
+} // namespace boost
+
+#endif // BOOST_MATH_SQRT1PM1
+
+
+
+
+