annotate DEPENDENCIES/generic/include/boost/math/special_functions/sqrt1pm1.hpp @ 133:4acb5d8d80b6 tip

Don't fail environmental check if README.md exists (but .txt and no-suffix don't)
author Chris Cannam
date Tue, 30 Jul 2019 12:25:44 +0100
parents c530137014c0
children
rev   line source
Chris@16 1 // (C) Copyright John Maddock 2006.
Chris@16 2 // Use, modification and distribution are subject to the
Chris@16 3 // Boost Software License, Version 1.0. (See accompanying file
Chris@16 4 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16 5
Chris@16 6 #ifndef BOOST_MATH_SQRT1PM1
Chris@16 7 #define BOOST_MATH_SQRT1PM1
Chris@16 8
Chris@16 9 #ifdef _MSC_VER
Chris@16 10 #pragma once
Chris@16 11 #endif
Chris@16 12
Chris@101 13 #include <boost/math/special_functions/math_fwd.hpp>
Chris@16 14 #include <boost/math/special_functions/log1p.hpp>
Chris@16 15 #include <boost/math/special_functions/expm1.hpp>
Chris@16 16
Chris@16 17 //
Chris@16 18 // This algorithm computes sqrt(1+x)-1 for small x:
Chris@16 19 //
Chris@16 20
Chris@16 21 namespace boost{ namespace math{
Chris@16 22
Chris@16 23 template <class T, class Policy>
Chris@16 24 inline typename tools::promote_args<T>::type sqrt1pm1(const T& val, const Policy& pol)
Chris@16 25 {
Chris@16 26 typedef typename tools::promote_args<T>::type result_type;
Chris@16 27 BOOST_MATH_STD_USING
Chris@16 28
Chris@16 29 if(fabs(result_type(val)) > 0.75)
Chris@16 30 return sqrt(1 + result_type(val)) - 1;
Chris@16 31 return boost::math::expm1(boost::math::log1p(val, pol) / 2, pol);
Chris@16 32 }
Chris@16 33
Chris@16 34 template <class T>
Chris@16 35 inline typename tools::promote_args<T>::type sqrt1pm1(const T& val)
Chris@16 36 {
Chris@16 37 return sqrt1pm1(val, policies::policy<>());
Chris@16 38 }
Chris@16 39
Chris@16 40 } // namespace math
Chris@16 41 } // namespace boost
Chris@16 42
Chris@16 43 #endif // BOOST_MATH_SQRT1PM1
Chris@16 44
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Chris@16 48