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1// (C) Copyright John Maddock 2006.2// (C) Copyright Johan Rade 2006.3// (C) Copyright Paul A. Bristow 2011 (added changesign).4// (C) Copyright Matt Borland 20245 6// Use, modification and distribution are subject to the7// Boost Software License, Version 1.0. (See accompanying file8// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)9 10#ifndef BOOST_MATH_TOOLS_SIGN_HPP11#define BOOST_MATH_TOOLS_SIGN_HPP12 13#ifdef _MSC_VER14#pragma once15#endif16 17#ifndef __CUDACC_RTC__18 19#include <boost/math/tools/config.hpp>20#include <boost/math/special_functions/math_fwd.hpp>21#include <boost/math/special_functions/detail/fp_traits.hpp>22 23namespace boost{ namespace math{ 24 25namespace detail {26 27 // signbit28 29#ifdef BOOST_MATH_USE_STD_FPCLASSIFY30 template<class T> 31 BOOST_MATH_GPU_ENABLED inline int signbit_impl(T x, native_tag const&)32 {33 using std::signbit;34 return (signbit)(x) ? 1 : 0;35 }36#endif37 38 // Generic versions first, note that these do not handle39 // signed zero or NaN.40 41 template<class T>42 BOOST_MATH_GPU_ENABLED inline int signbit_impl(T x, generic_tag<true> const&)43 {44 return x < 0;45 }46 47 template<class T> 48 BOOST_MATH_GPU_ENABLED inline int signbit_impl(T x, generic_tag<false> const&)49 {50 return x < 0;51 }52 53#if defined(__GNUC__) && (LDBL_MANT_DIG == 106)54 //55 // Special handling for GCC's "double double" type, 56 // in this case the sign is the same as the sign we57 // get by casting to double, no overflow/underflow58 // can occur since the exponents are the same magnitude59 // for the two types:60 //61 inline int signbit_impl(long double x, generic_tag<true> const&)62 {63 return (boost::math::signbit)(static_cast<double>(x));64 }65 inline int signbit_impl(long double x, generic_tag<false> const&)66 {67 return (boost::math::signbit)(static_cast<double>(x));68 }69#endif70 71 template<class T>72 BOOST_MATH_GPU_ENABLED inline int signbit_impl(T x, ieee_copy_all_bits_tag const&)73 {74 typedef typename fp_traits<T>::type traits;75 76 typename traits::bits a;77 traits::get_bits(x,a);78 return a & traits::sign ? 1 : 0;79 }80 81 template<class T> 82 BOOST_MATH_GPU_ENABLED inline int signbit_impl(T x, ieee_copy_leading_bits_tag const&)83 {84 typedef typename fp_traits<T>::type traits;85 86 typename traits::bits a;87 traits::get_bits(x,a);88 89 return a & traits::sign ? 1 : 0;90 }91 92 // Changesign93 94 // Generic versions first, note that these do not handle95 // signed zero or NaN.96 97 template<class T>98 BOOST_MATH_GPU_ENABLED inline T (changesign_impl)(T x, generic_tag<true> const&)99 {100 return -x;101 }102 103 template<class T>104 BOOST_MATH_GPU_ENABLED inline T (changesign_impl)(T x, generic_tag<false> const&)105 {106 return -x;107 }108#if defined(__GNUC__) && (LDBL_MANT_DIG == 106)109 //110 // Special handling for GCC's "double double" type, 111 // in this case we need to change the sign of both112 // components of the "double double":113 //114 inline long double (changesign_impl)(long double x, generic_tag<true> const&)115 {116 double* pd = reinterpret_cast<double*>(&x);117 pd[0] = boost::math::changesign(pd[0]);118 pd[1] = boost::math::changesign(pd[1]);119 return x;120 }121 inline long double (changesign_impl)(long double x, generic_tag<false> const&)122 {123 double* pd = reinterpret_cast<double*>(&x);124 pd[0] = boost::math::changesign(pd[0]);125 pd[1] = boost::math::changesign(pd[1]);126 return x;127 }128#endif129 130 template<class T>131 BOOST_MATH_GPU_ENABLED inline T changesign_impl(T x, ieee_copy_all_bits_tag const&)132 {133 typedef typename fp_traits<T>::sign_change_type traits;134 135 typename traits::bits a;136 traits::get_bits(x,a);137 a ^= traits::sign;138 traits::set_bits(x,a);139 return x;140 }141 142 template<class T>143 BOOST_MATH_GPU_ENABLED inline T (changesign_impl)(T x, ieee_copy_leading_bits_tag const&)144 {145 typedef typename fp_traits<T>::sign_change_type traits;146 147 typename traits::bits a;148 traits::get_bits(x,a);149 a ^= traits::sign;150 traits::set_bits(x,a);151 return x;152 }153 154 155} // namespace detail156 157template<class T> 158BOOST_MATH_GPU_ENABLED int (signbit)(T x)159{ 160 typedef typename detail::fp_traits<T>::type traits;161 typedef typename traits::method method;162 // typedef typename boost::is_floating_point<T>::type fp_tag;163 typedef typename tools::promote_args_permissive<T>::type result_type;164 return detail::signbit_impl(static_cast<result_type>(x), method());165}166 167template <class T>168BOOST_MATH_GPU_ENABLED inline int sign BOOST_NO_MACRO_EXPAND(const T& z)169{170 return (z == 0) ? 0 : (boost::math::signbit)(z) ? -1 : 1;171}172 173template <class T> 174BOOST_MATH_GPU_ENABLED typename tools::promote_args_permissive<T>::type (changesign)(const T& x)175{ //!< \brief return unchanged binary pattern of x, except for change of sign bit. 176 typedef typename detail::fp_traits<T>::sign_change_type traits;177 typedef typename traits::method method;178 // typedef typename boost::is_floating_point<T>::type fp_tag;179 typedef typename tools::promote_args_permissive<T>::type result_type;180 181 return detail::changesign_impl(static_cast<result_type>(x), method());182}183 184template <class T, class U>185BOOST_MATH_GPU_ENABLED inline typename tools::promote_args_permissive<T, U>::type 186 copysign BOOST_NO_MACRO_EXPAND(const T& x, const U& y)187{188 BOOST_MATH_STD_USING189 typedef typename tools::promote_args_permissive<T, U>::type result_type;190 return (boost::math::signbit)(static_cast<result_type>(x)) != (boost::math::signbit)(static_cast<result_type>(y)) 191 ? (boost::math::changesign)(static_cast<result_type>(x)) : static_cast<result_type>(x);192}193 194} // namespace math195} // namespace boost196 197#else // NVRTC alias versions198 199#include <boost/math/tools/config.hpp>200 201namespace boost {202namespace math {203 204template <typename T>205BOOST_MATH_GPU_ENABLED int signbit(T x)206{207 return ::signbit(x);208}209 210template <typename T>211BOOST_MATH_GPU_ENABLED T changesign(T x)212{213 return -x;214}215 216template <typename T>217BOOST_MATH_GPU_ENABLED T copysign(T x, T y)218{219 return ::copysign(x, y);220}221 222template <>223BOOST_MATH_GPU_ENABLED float copysign(float x, float y)224{225 return ::copysignf(x, y);226}227 228template <typename T>229BOOST_MATH_GPU_ENABLED T sign(T z)230{231 return (z == 0) ? 0 : ::signbit(z) ? -1 : 1;232}233 234} // namespace math235} // namespace boost236 237#endif // __CUDACC_RTC__238 239#endif // BOOST_MATH_TOOLS_SIGN_HPP240 241 242