From 8e8f6ec4be96723b0ce9399bbc297b02a7da4fe1 Mon Sep 17 00:00:00 2001 From: Matt Borland <matt@mattborland.com> Date: Wed, 6 Oct 2021 20:42:02 +0300 Subject: [PATCH] constexpr remainder (#700) --- doc/sf/ccmath.qbk | 6 + include/boost/math/ccmath/ccmath.hpp | 1 + include/boost/math/ccmath/remainder.hpp | 107 ++++++++++++++++++ test/Jamfile.v2 | 1 + test/ccmath_remainder_test.cpp | 85 ++++++++++++++ .../ccmath_remainder_incl_test.cpp | 16 +++ 6 files changed, 216 insertions(+) create mode 100644 include/boost/math/ccmath/remainder.hpp create mode 100644 test/ccmath_remainder_test.cpp create mode 100644 test/compile_test/ccmath_remainder_incl_test.cpp diff --git a/doc/sf/ccmath.qbk b/doc/sf/ccmath.qbk index 4f19f919ad..373a7b9530 100644 --- a/doc/sf/ccmath.qbk +++ b/doc/sf/ccmath.qbk @@ -131,6 +131,12 @@ All of the following functions require C++17 or greater. inline constexpr Promoted fmod(Arithmetic1 x, Arithmetic2 y) noexcept The Promoted return type will have at least double prescision, but be up to the highest precision argument. + template <typename Real> + inline constexpr Real remainder(Real x, Real y) noexcept + + template <typename Arithmetic1, typename Arithmetic2> + inline constexpr Promoted remainder(Arithmetic1 x, Arithmetic2 y) noexcept + } // Namespaces [endsect] [/section:ccmath Constexpr CMath] diff --git a/include/boost/math/ccmath/ccmath.hpp b/include/boost/math/ccmath/ccmath.hpp index de7d1d9fa5..8f5cb0edf2 100644 --- a/include/boost/math/ccmath/ccmath.hpp +++ b/include/boost/math/ccmath/ccmath.hpp @@ -27,5 +27,6 @@ #include <boost/math/ccmath/modf.hpp> #include <boost/math/ccmath/round.hpp> #include <boost/math/ccmath/fmod.hpp> +#include <boost/math/ccmath/remainder.hpp> #endif // BOOST_MATH_CCMATH_HPP diff --git a/include/boost/math/ccmath/remainder.hpp b/include/boost/math/ccmath/remainder.hpp new file mode 100644 index 0000000000..cf642efa40 --- /dev/null +++ b/include/boost/math/ccmath/remainder.hpp @@ -0,0 +1,107 @@ +// (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_REMAINDER_HPP +#define BOOST_MATH_CCMATH_REMAINDER_HPP + +#include <cmath> +#include <cstdint> +#include <limits> +#include <type_traits> +#include <boost/math/tools/is_constant_evaluated.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> +inline constexpr T remainder_impl(const T x, const T y) noexcept +{ + T n = 0; + const T fractional_part = boost::math::ccmath::modf((x / y), &n); + + if(fractional_part > T(1.0/2)) + { + ++n; + } + else if(fractional_part < 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> +inline constexpr Real remainder(Real x, Real y) noexcept +{ + if(BOOST_MATH_IS_CONSTANT_EVALUATED(x)) + { + return boost::math::ccmath::isinf(x) && !boost::math::ccmath::isnan(y) ? std::numeric_limits<Real>::quiet_NaN() : + boost::math::ccmath::abs(y) == Real(0) && !boost::math::ccmath::isnan(x) ? std::numeric_limits<Real>::quiet_NaN() : + boost::math::ccmath::isnan(x) || boost::math::ccmath::isnan(y) ? std::numeric_limits<Real>::quiet_NaN() : + boost::math::ccmath::detail::remainder_impl<Real>(x, y); + } + else + { + using std::remainder; + return remainder(x, y); + } +} + +template <typename T1, typename T2> +inline constexpr auto remainder(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::remainder(promoted_type(x), promoted_type(y)); + } + else + { + using std::remainder; + return remainder(x, y); + } +} + +inline constexpr float remainderf(float x, float y) noexcept +{ + return boost::math::ccmath::remainder(x, y); +} + +#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS +inline constexpr long double remainderl(long double x, long double y) noexcept +{ + return boost::math::ccmath::remainder(x, y); +} +#endif + +} // Namespaces + +#endif // BOOST_MATH_CCMATH_REMAINDER_HPP diff --git a/test/Jamfile.v2 b/test/Jamfile.v2 index cc2f4ebada..9b06070d2c 100644 --- a/test/Jamfile.v2 +++ b/test/Jamfile.v2 @@ -141,6 +141,7 @@ test-suite special_fun : [ run ccmath_modf_test.cpp ../../test/build//boost_unit_test_framework : : : [ requires cxx17_if_constexpr ] ] [ 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 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 ] diff --git a/test/ccmath_remainder_test.cpp b/test/ccmath_remainder_test.cpp new file mode 100644 index 0000000000..ac5ebd9817 --- /dev/null +++ b/test/ccmath_remainder_test.cpp @@ -0,0 +1,85 @@ +// (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/remainder.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() +{ + // Error Handling + if constexpr (std::numeric_limits<T>::has_quiet_NaN) + { + static_assert(boost::math::ccmath::isnan(boost::math::ccmath::remainder(std::numeric_limits<T>::quiet_NaN(), T(1))), "If x is NaN, NaN is returned"); + static_assert(boost::math::ccmath::isnan(boost::math::ccmath::remainder(T(1), std::numeric_limits<T>::quiet_NaN())), "If y is NaN, NaN is returned"); + } + + static_assert(boost::math::ccmath::isnan(boost::math::ccmath::remainder(std::numeric_limits<T>::infinity(), T(1)))); + static_assert(boost::math::ccmath::isnan(boost::math::ccmath::remainder(-std::numeric_limits<T>::infinity(), T(1)))); + static_assert(boost::math::ccmath::isnan(boost::math::ccmath::remainder(T(1), T(0)))); + static_assert(boost::math::ccmath::isnan(boost::math::ccmath::remainder(T(1), T(-0)))); + + // Functionality + static_assert(boost::math::ccmath::remainder(T(6), T(2)) == T(0)); + static_assert(boost::math::ccmath::remainder(T(3.0/2), T(1.0) == T(3.0/2))); + static_assert(boost::math::ccmath::remainder(T(7.0/3), T(2.0) == T(1.0/3))); + static_assert(boost::math::ccmath::remainder(T(-8.0/3), T(2.0) == T(-2.0/3))); + static_assert(boost::math::ccmath::remainder(T(-0), T(1)) == T(-0)); + + // Not exact values but pulled from https://en.cppreference.com/w/cpp/numeric/math/remainder as general functionality tests so allow for some error + // std::is_floating_point_v excludes multi-precision types + if constexpr (std::is_floating_point_v<T>) + { + static_assert(boost::math::ccmath::abs(boost::math::ccmath::remainder(T(5.1l), T(3.0l)) - T(-0.9l)) < 2*std::numeric_limits<T>::epsilon()); + static_assert(boost::math::ccmath::abs(boost::math::ccmath::remainder(T(-5.1l), T(3.0l)) - T(0.9l)) < 2*std::numeric_limits<T>::epsilon()); + static_assert(boost::math::ccmath::abs(boost::math::ccmath::remainder(T(5.1l), T(-3.0l)) - T(-0.9l)) < 2*std::numeric_limits<T>::epsilon()); + static_assert(boost::math::ccmath::abs(boost::math::ccmath::remainder(T(-5.1l), T(-3.0l)) - T(0.9l)) < 2*std::numeric_limits<T>::epsilon()); + } + + // Correct promoted types + if constexpr (!std::is_same_v<T, float>) + { + constexpr auto test_type = boost::math::ccmath::remainder(T(1), 1.0f); + static_assert(std::is_same_v<T, std::remove_cv_t<decltype(test_type)>>); + } + else + { + constexpr auto test_type = boost::math::ccmath::remainder(1.0f, 1); + static_assert(std::is_same_v<double, std::remove_cv_t<decltype(test_type)>>); + } +} + +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 \ No newline at end of file diff --git a/test/compile_test/ccmath_remainder_incl_test.cpp b/test/compile_test/ccmath_remainder_incl_test.cpp new file mode 100644 index 0000000000..fb16ce3f02 --- /dev/null +++ b/test/compile_test/ccmath_remainder_incl_test.cpp @@ -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/remainder.hpp> +#include "test_compile_result.hpp" + +void compile_and_link_test() +{ + check_result<float>(boost::math::ccmath::remainder(1.0f, 1.0f)); + check_result<double>(boost::math::ccmath::remainder(1.0, 1.0)); +#ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS + check_result<long double>(boost::math::ccmath::remainder(1.0l, 1.0l)); +#endif +}