boost/math
2
0
Fork 0
mirror of https://github.com/boostorg/math.git synced 2026-01-19 04:22:09 +00:00
Code Issues Projects Releases Wiki Activity

Constexpr fdim (#730)

Browse Source
This commit is contained in:
Matt Borland
2022-01-05 17:01:22 +02:00
committed by GitHub
parent e8edbb9ac3
commit 3ce09d5739
6 changed files with 178 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
doc/sf/ccmath.qbk
View File

@@ -149,6 +149,12 @@ All of the following functions require C++17 or greater.
template <typename Arithmetic1, typename Arithmetic2>
inline constexpr Promoted hypot(Arithmetic1 x, Arithmetic2 y) noexcept
template <typename Real>
inline constexpr Real fdim(Real x, Real y) noexcept
template <typename Arithmetic1, typename Arithmetic2>
inline constexpr Promoted fdim(Arithmetic1 x, Arithmetic2 y) noexcept
} // Namespaces
[endsect] [/section:ccmath Constexpr CMath]

1
include/boost/math/ccmath/ccmath.hpp
View File

@@ -30,5 +30,6 @@
#include <boost/math/ccmath/remainder.hpp>
#include <boost/math/ccmath/copysign.hpp>
#include <boost/math/ccmath/hypot.hpp>
#include <boost/math/ccmath/fdim.hpp>
#endif // BOOST_MATH_CCMATH_HPP

100
include/boost/math/ccmath/fdim.hpp Normal file
View File

@@ -0,0 +1,100 @@
// (C) Copyright Matt Borland 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_FDIM_HPP
#define BOOST_MATH_CCMATH_FDIM_HPP
#include <cmath>
#include <limits>
#include <type_traits>
#include <boost/math/tools/is_constant_evaluated.hpp>
#include <boost/math/ccmath/isnan.hpp>
namespace boost::math::ccmath {
namespace detail {
template <typename T>
inline constexpr T fdim_impl(const T x, const T y) noexcept
{
if (x <= y)
{
return 0;
}
else if ((y < 0) && (x > (std::numeric_limits<T>::max)() + y))
{
return std::numeric_limits<T>::infinity();
}
else
{
return x - y;
}
}
} // Namespace detail
template <typename Real, std::enable_if_t<!std::is_integral_v<Real>, bool> = true>
inline constexpr Real fdim(Real x, Real y) noexcept
{
if (BOOST_MATH_IS_CONSTANT_EVALUATED(x))
{
return boost::math::ccmath::isnan(x) ? std::numeric_limits<Real>::quiet_NaN() :
boost::math::ccmath::isnan(y) ? std::numeric_limits<Real>::quiet_NaN() :
boost::math::ccmath::detail::fdim_impl(x, y);
}
else
{
using std::fdim;
return fdim(x, y);
}
}
template <typename T1, typename T2>
inline constexpr auto fdim(T1 x, T2 y) noexcept
{
if (BOOST_MATH_IS_CONSTANT_EVALUATED(x))
{
// 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::fdim(promoted_type(x), promoted_type(y));
}
else
{
using std::fdim;
return fdim(x, y);
}
}
inline constexpr float fdimf(float x, float y) noexcept
{
return boost::math::ccmath::fdim(x, y);
}
#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
inline constexpr long double fdiml(long double x, long double y) noexcept
{
return boost::math::ccmath::fdim(x, y);
}
#endif
} // Namespace boost::math::ccmath
#endif // BOOST_MATH_CCMATH_FDIM_HPP

1
test/Jamfile.v2
View File

@@ -144,6 +144,7 @@ test-suite special_fun :
[ 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 ccmath_hypot_test.cpp ../../test/build//boost_unit_test_framework : : : [ requires cxx17_if_constexpr ] ]
[ run ccmath_fdim_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 git_issue_705.cpp ../../test/build//boost_unit_test_framework ]

54
test/ccmath_fdim_test.cpp Normal file
View File

@@ -0,0 +1,54 @@
// (C) Copyright Matt Borland 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)
#include <cmath>
#include <cfloat>
#include <cstdint>
#include <limits>
#include <type_traits>
#include <boost/math/ccmath/fdim.hpp>
#include <boost/math/ccmath/isnan.hpp>
#include <boost/math/ccmath/isinf.hpp>
#ifdef BOOST_HAS_FLOAT128
#include <boost/multiprecision/float128.hpp>
#endif
template <typename T>
constexpr void test()
{
static_assert(boost::math::ccmath::isnan(boost::math::ccmath::fdim(std::numeric_limits<T>::quiet_NaN(), T(1))), "If x is NaN, NaN is returned");
static_assert(boost::math::ccmath::isnan(boost::math::ccmath::fdim(T(1), std::numeric_limits<T>::quiet_NaN())), "If y is NaN, NaN is returned");
static_assert(boost::math::ccmath::fdim(T(4), T(1)) == T(3));
static_assert(boost::math::ccmath::fdim(T(1), T(4)) == T(0));
static_assert(boost::math::ccmath::fdim(T(4), T(-1)) == T(5));
static_assert(boost::math::ccmath::fdim(T(1), T(-4)) == T(5));
static_assert(boost::math::ccmath::isinf(boost::math::ccmath::fdim(std::numeric_limits<T>::infinity(), T(-1))));
}
#if !defined(BOOST_MATH_NO_CONSTEXPR_DETECTION) && !defined(BOOST_MATH_USING_BUILTIN_CONSTANT_P)
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_fdim_incl_test.cpp Normal file
View File

@@ -0,0 +1,16 @@
// (C) Copyright Matt Borland 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)
#include <boost/math/ccmath/fdim.hpp>
#include "test_compile_result.hpp"
void compile_and_link_test()
{
check_result<float>(boost::math::ccmath::fdim(1.0f, 1.0f));
check_result<double>(boost::math::ccmath::fdim(1.0, 1.0));
#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
check_result<long double>(boost::math::ccmath::fdim(1.0l, 1.0l));
#endif
}