80 lines
2.0 KiB
C++
80 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_SCALBN_HPP
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#define BOOST_MATH_CCMATH_SCALBN_HPP
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#include <cmath>
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#include <cfloat>
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#include <limits>
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#include <type_traits>
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#include <boost/math/tools/is_constant_evaluated.hpp>
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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, typename Z>
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inline constexpr Real scalbn_impl(Real arg, Z exp) noexcept
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{
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while(exp > 0)
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{
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arg *= FLT_RADIX;
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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 /= FLT_RADIX;
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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 scalbn(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::scalbn_impl(arg, exp);
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}
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else
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{
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using std::scalbn;
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return scalbn(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 scalbn(Z arg, int exp) noexcept
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{
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return boost::math::ccmath::scalbn(static_cast<double>(arg), exp);
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}
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inline constexpr float scalbnf(float arg, int exp) noexcept
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{
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return boost::math::ccmath::scalbn(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 scalbnl(long double arg, int exp) noexcept
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{
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return boost::math::ccmath::scalbn(arg, exp);
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}
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#endif
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} // Namespaces
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#endif // BOOST_MATH_CCMATH_SCALBN_HPP
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