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constexpr copysign (#701)

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* constexpr copysign

* Fix for mingw test failure
This commit is contained in:
Matt Borland
2021-10-10 20:38:26 +03:00
committed by GitHub
parent 8e8f6ec4be
commit 7339acd01a
6 changed files with 174 additions and 0 deletions
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6
doc/sf/ccmath.qbk
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@@ -137,6 +137,12 @@ All of the following functions require C++17 or greater.
template <typename Arithmetic1, typename Arithmetic2>
inline constexpr Promoted remainder(Arithmetic1 x, Arithmetic2 y) noexcept
template <typename Real>
inline constexpr Real copysign(Real mag, Real sgn) noexcept
template <typename Arithmetic1, typename Arithmetic2>
inline constexpr Promoted copysign(Arithmetic1 mag, Arithmetic2 sgn) noexcept
} // Namespaces
[endsect] [/section:ccmath Constexpr CMath]

1
include/boost/math/ccmath/ccmath.hpp
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@@ -28,5 +28,6 @@
#include <boost/math/ccmath/round.hpp>
#include <boost/math/ccmath/fmod.hpp>
#include <boost/math/ccmath/remainder.hpp>
#include <boost/math/ccmath/copysign.hpp>
#endif // BOOST_MATH_CCMATH_HPP

95
include/boost/math/ccmath/copysign.hpp Normal file
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@@ -0,0 +1,95 @@
// (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_COPYSIGN_HPP
#define BOOST_MATH_CCMATH_COPYSIGN_HPP
#include <cmath>
#include <cstdint>
#include <limits>
#include <type_traits>
#include <boost/math/tools/is_constant_evaluated.hpp>
#include <boost/math/ccmath/abs.hpp>
namespace boost::math::ccmath {
namespace detail {
template <typename T>
inline constexpr T copysign_impl(const T mag, const T sgn) noexcept
{
if(sgn >= 0)
{
return boost::math::ccmath::abs(mag);
}
else
{
return -boost::math::ccmath::abs(mag);
}
}
} // Namespace detail
template <typename Real, std::enable_if_t<!std::is_integral_v<Real>, bool> = true>
inline constexpr Real copysign(Real mag, Real sgn) noexcept
{
if(BOOST_MATH_IS_CONSTANT_EVALUATED(mag))
{
return boost::math::ccmath::detail::copysign_impl(mag, sgn);
}
else
{
using std::copysign;
return copysign(mag, sgn);
}
}
template <typename T1, typename T2>
inline constexpr auto copysign(T1 mag, T2 sgn) noexcept
{
if(BOOST_MATH_IS_CONSTANT_EVALUATED(mag))
{
// If the type is an integer (e.g. epsilon == 0) then set the epsilon value to 1 so that type is at a minimum
// cast to double
constexpr auto T1p = std::numeric_limits<T1>::epsilon() > 0 ? std::numeric_limits<T1>::epsilon() : 1;
constexpr auto T2p = std::numeric_limits<T2>::epsilon() > 0 ? std::numeric_limits<T2>::epsilon() : 1;
using promoted_type =
#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
std::conditional_t<T1p <= LDBL_EPSILON && T1p <= T2p, T1,
std::conditional_t<T2p <= LDBL_EPSILON && T2p <= T1p, T2,
#endif
std::conditional_t<T1p <= DBL_EPSILON && T1p <= T2p, T1,
std::conditional_t<T2p <= DBL_EPSILON && T2p <= T1p, T2, double
#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
>>>>;
#else
>>;
#endif
return boost::math::ccmath::copysign(promoted_type(mag), promoted_type(sgn));
}
else
{
using std::copysign;
return copysign(mag, sgn);
}
}
inline constexpr float copysignf(float mag, float sgn) noexcept
{
return boost::math::ccmath::copysign(mag, sgn);
}
#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
inline constexpr long double copysignl(long double mag, long double sgn) noexcept
{
return boost::math::ccmath::copysign(mag, sgn);
}
#endif
} // Namespaces
#endif // BOOST_MATH_CCMATH_COPYSIGN_HPP

1
test/Jamfile.v2
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@@ -142,6 +142,7 @@ test-suite special_fun :
[ run ccmath_round_test.cpp ../../test/build//boost_unit_test_framework : : : [ requires cxx17_if_constexpr ] ]
[ run ccmath_fmod_test.cpp ../../test/build//boost_unit_test_framework : : : [ requires cxx17_if_constexpr ] ]
[ run ccmath_remainder_test.cpp ../../test/build//boost_unit_test_framework : : : [ requires cxx17_if_constexpr ] ]
[ run ccmath_copysign_test.cpp ../../test/build//boost_unit_test_framework : : : [ requires cxx17_if_constexpr ] ]
[ run log1p_expm1_test.cpp test_instances//test_instances pch_light ../../test/build//boost_unit_test_framework ]
[ run powm1_sqrtp1m1_test.cpp test_instances//test_instances pch_light ../../test/build//boost_unit_test_framework ]
[ run special_functions_test.cpp ../../test/build//boost_unit_test_framework ]

55
test/ccmath_copysign_test.cpp Normal file
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@@ -0,0 +1,55 @@
// (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)
#include <cmath>
#include <cfloat>
#include <cstdint>
#include <limits>
#include <type_traits>
#include <boost/math/ccmath/copysign.hpp>
#include <boost/math/ccmath/isnan.hpp>
#include <boost/math/ccmath/isinf.hpp>
#ifdef BOOST_HAS_FLOAT128
#include <boost/multiprecision/float128.hpp>
#endif
#if !defined(BOOST_MATH_NO_CONSTEXPR_DETECTION) && !defined(BOOST_MATH_USING_BUILTIN_CONSTANT_P)
template <typename T>
constexpr void test()
{
if constexpr (std::numeric_limits<T>::has_quiet_NaN)
{
static_assert(boost::math::ccmath::isnan(boost::math::ccmath::copysign(std::numeric_limits<T>::quiet_NaN(), T(1))));
static_assert(boost::math::ccmath::isnan(boost::math::ccmath::copysign(std::numeric_limits<T>::quiet_NaN(), T(-1))));
}
static_assert(boost::math::ccmath::copysign(T(1), T(2)) == T(1));
static_assert(boost::math::ccmath::copysign(T(1), T(-2)) == T(-1));
static_assert(boost::math::ccmath::copysign(std::numeric_limits<T>::infinity(), T(2)) == std::numeric_limits<T>::infinity());
static_assert(boost::math::ccmath::copysign(std::numeric_limits<T>::infinity(), T(-2)) == -std::numeric_limits<T>::infinity());
}
int main()
{
test<float>();
test<double>();
#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
test<long double>();
#endif
#ifdef BOOST_HAS_FLOAT128
test<boost::multiprecision::float128>();
#endif
return 0;
}
#else
int main()
{
return 0;
}
#endif

16
test/compile_test/ccmath_copysign_incl_test.cpp Normal file
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@@ -0,0 +1,16 @@
// (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)
#include <boost/math/ccmath/copysign.hpp>
#include "test_compile_result.hpp"
void compile_and_link_test()
{
check_result<float>(boost::math::ccmath::copysign(1.0f, 1.0f));
check_result<double>(boost::math::ccmath::copysign(1.0, 1.0));
#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
check_result<long double>(boost::math::ccmath::copysign(1.0l, 1.0l));
#endif
}