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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2.6 KiB
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// (C) Copyright Matt Borland 2021 - 2022.
// 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_REMAINDER_HPP
#define BOOST_MATH_CCMATH_REMAINDER_HPP
#include <boost/math/ccmath/detail/config.hpp>
#ifdef BOOST_MATH_NO_CCMATH
#error "The header <boost/math/remainder.hpp> can only be used in C++17 and later."
#endif
#include <cstdint>
#include <boost/math/tools/promotion.hpp>
#include <boost/math/ccmath/abs.hpp>
#include <boost/math/ccmath/isinf.hpp>
#include <boost/math/ccmath/isnan.hpp>
#include <boost/math/ccmath/isfinite.hpp>
#include <boost/math/ccmath/modf.hpp>
namespace boost::math::ccmath {
namespace detail {
template <typename T>
constexpr T remainder_impl(const T x, const T y)
{
T n = 0;
if (T fractional_part = boost::math::ccmath::modf((x / y), &n); fractional_part > static_cast<T>(1.0/2))
{
++n;
}
else if (fractional_part < static_cast<T>(-1.0/2))
{
--n;
}
return x - n*y;
}
} // Namespace detail
template <typename Real, std::enable_if_t<!std::is_integral_v<Real>, bool> = true>
constexpr Real remainder(Real x, Real y)
{
if (BOOST_MATH_IS_CONSTANT_EVALUATED(x))
{
if (boost::math::ccmath::isinf(x) && !boost::math::ccmath::isnan(y))
{
return std::numeric_limits<Real>::quiet_NaN();
}
else if (boost::math::ccmath::abs(y) == static_cast<Real>(0) && !boost::math::ccmath::isnan(x))
{
return std::numeric_limits<Real>::quiet_NaN();
}
else if (boost::math::ccmath::isnan(x))
{
return x;
}
else if (boost::math::ccmath::isnan(y))
{
return y;
}
return boost::math::ccmath::detail::remainder_impl(x, y);
}
else
{
using std::remainder;
return remainder(x, y);
}
}
template <typename T1, typename T2>
constexpr auto remainder(T1 x, T2 y)
{
if (BOOST_MATH_IS_CONSTANT_EVALUATED(x))
{
using promoted_type = boost::math::tools::promote_args_t<T1, T2>;
return boost::math::ccmath::remainder(promoted_type(x), promoted_type(y));
}
else
{
using std::remainder;
return remainder(x, y);
}
}
constexpr float remainderf(float x, float y)
{
return boost::math::ccmath::remainder(x, y);
}
#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
constexpr long double remainderl(long double x, long double y)
{
return boost::math::ccmath::remainder(x, y);
}
#endif
} // Namespaces
#endif // BOOST_MATH_CCMATH_REMAINDER_HPP