585da50d7d
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
82 lines
2.0 KiB
C++
82 lines
2.0 KiB
C++
// (C) Copyright Matt Borland 2021.
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// (C) Copyright John Maddock 2021.
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// Use, modification and distribution are subject to the
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// Boost Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_MATH_CCMATH_LDEXP_HPP
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#define BOOST_MATH_CCMATH_LDEXP_HPP
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#include <boost/math/ccmath/detail/config.hpp>
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#ifdef BOOST_MATH_NO_CCMATH
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#error "The header <boost/math/ldexp.hpp> can only be used in C++17 and later."
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#endif
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#include <stdexcept>
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#include <boost/math/ccmath/abs.hpp>
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#include <boost/math/ccmath/isinf.hpp>
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#include <boost/math/ccmath/isnan.hpp>
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namespace boost::math::ccmath {
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namespace detail {
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template <typename Real>
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inline constexpr Real ldexp_impl(Real arg, int exp) noexcept
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{
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while(exp > 0)
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{
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arg *= 2;
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--exp;
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}
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while(exp < 0)
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{
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arg /= 2;
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++exp;
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}
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return arg;
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}
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} // Namespace detail
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template <typename Real, std::enable_if_t<!std::is_integral_v<Real>, bool> = true>
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inline constexpr Real ldexp(Real arg, int exp) noexcept
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{
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if(BOOST_MATH_IS_CONSTANT_EVALUATED(arg))
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{
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return boost::math::ccmath::abs(arg) == Real(0) ? arg :
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(boost::math::ccmath::isinf)(arg) ? arg :
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(boost::math::ccmath::isnan)(arg) ? arg :
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boost::math::ccmath::detail::ldexp_impl(arg, exp);
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}
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else
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{
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using std::ldexp;
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return ldexp(arg, exp);
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}
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}
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template <typename Z, std::enable_if_t<std::is_integral_v<Z>, bool> = true>
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inline constexpr double ldexp(Z arg, int exp) noexcept
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{
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return boost::math::ccmath::ldexp(static_cast<double>(arg), exp);
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}
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inline constexpr float ldexpf(float arg, int exp) noexcept
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{
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return boost::math::ccmath::ldexp(arg, exp);
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}
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#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
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inline constexpr long double ldexpl(long double arg, int exp) noexcept
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{
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return boost::math::ccmath::ldexp(arg, exp);
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}
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#endif
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} // Namespaces
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#endif // BOOST_MATH_CCMATH_LDEXP_HPP
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