Louis Dionne 585da50d7d
[third-party] Add a snapshot of Boost.Math 1.89 standalone (#141508)
This PR adds the code of Boost.Math as of version 1.89 into the
third-party directory, as discussed in a recent RFC [1].

The goal is for this code to be used as a back-end for the C++17
Math Special Functions.

As explained in third-paty/README.md, this code is cleared for
usage inside libc++ for the Math Special functions, however
the LLVM Foundation should be consulted before using this
code anywhere else in the LLVM project, due to the fact
that it is under the Boost Software License (as opposed
to the usual LLVM license). See the RFC [1] for more details.

[1]: https://discourse.llvm.org/t/rfc-libc-taking-a-dependency-on-boost-math-for-the-c-17-math-special-functions
2025-10-27 14:43:57 -07:00

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1.7 KiB
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// (C) Copyright Matt Borland 2021.
// 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_CCMATH_SCALBLN_HPP
#define BOOST_MATH_CCMATH_SCALBLN_HPP
#include <boost/math/ccmath/detail/config.hpp>
#ifdef BOOST_MATH_NO_CCMATH
#error "The header <boost/math/scalbln.hpp> can only be used in C++17 and later."
#endif
#include <cfloat>
#include <boost/math/ccmath/scalbn.hpp>
#include <boost/math/ccmath/abs.hpp>
#include <boost/math/ccmath/isinf.hpp>
#include <boost/math/ccmath/isnan.hpp>
namespace boost::math::ccmath {
template <typename Real, std::enable_if_t<!std::is_integral_v<Real>, bool> = true>
inline constexpr Real scalbln(Real arg, long exp) noexcept
{
if(BOOST_MATH_IS_CONSTANT_EVALUATED(arg))
{
return boost::math::ccmath::abs(arg) == Real(0) ? arg :
boost::math::ccmath::isinf(arg) ? arg :
boost::math::ccmath::isnan(arg) ? arg :
boost::math::ccmath::detail::scalbn_impl(arg, exp);
}
else
{
using std::scalbln;
return scalbln(arg, exp);
}
}
template <typename Z, std::enable_if_t<std::is_integral_v<Z>, bool> = true>
inline constexpr double scalbln(Z arg, long exp) noexcept
{
return boost::math::ccmath::scalbln(static_cast<double>(arg), exp);
}
inline constexpr float scalblnf(float arg, long exp) noexcept
{
return boost::math::ccmath::scalbln(arg, exp);
}
#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
inline constexpr long double scalblnl(long double arg, long exp) noexcept
{
return boost::math::ccmath::scalbln(arg, exp);
}
#endif
} // Namespaces
#endif // BOOST_MATH_CCMATH_SCALBLN_HPP