1 // Special functions -*- C++ -*- 2 3 // Copyright (C) 2006-2018 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file tr1/special_function_util.h 26 * This is an internal header file, included by other library headers. 27 * Do not attempt to use it directly. @headername{tr1/cmath} 28 */ 29 30 // 31 // ISO C++ 14882 TR1: 5.2 Special functions 32 // 33 34 // Written by Edward Smith-Rowland based on numerous mathematics books. 35 36 #ifndef _GLIBCXX_TR1_SPECIAL_FUNCTION_UTIL_H 37 #define _GLIBCXX_TR1_SPECIAL_FUNCTION_UTIL_H 1 38 39 namespace std _GLIBCXX_VISIBILITY(default) 40 { 41 _GLIBCXX_BEGIN_NAMESPACE_VERSION 42 43 #if _GLIBCXX_USE_STD_SPEC_FUNCS 44 #elif defined(_GLIBCXX_TR1_CMATH) 45 namespace tr1 46 { 47 #else 48 # error do not include this header directly, use <cmath> or <tr1/cmath> 49 #endif 50 namespace __detail 51 { 52 /// A class to encapsulate type dependent floating point 53 /// constants. Not everything will be able to be expressed as 54 /// type logic. 55 template<typename _Tp> 56 struct __floating_point_constant 57 { 58 static const _Tp __value; 59 }; 60 61 62 /// A structure for numeric constants. 63 template<typename _Tp> 64 struct __numeric_constants 65 { 66 /// Constant @f$ \pi @f$. 67 static _Tp __pi() throw() 68 { return static_cast<_Tp>(3.1415926535897932384626433832795029L); } 69 /// Constant @f$ \pi / 2 @f$. 70 static _Tp __pi_2() throw() 71 { return static_cast<_Tp>(1.5707963267948966192313216916397514L); } 72 /// Constant @f$ \pi / 3 @f$. 73 static _Tp __pi_3() throw() 74 { return static_cast<_Tp>(1.0471975511965977461542144610931676L); } 75 /// Constant @f$ \pi / 4 @f$. 76 static _Tp __pi_4() throw() 77 { return static_cast<_Tp>(0.7853981633974483096156608458198757L); } 78 /// Constant @f$ 1 / \pi @f$. 79 static _Tp __1_pi() throw() 80 { return static_cast<_Tp>(0.3183098861837906715377675267450287L); } 81 /// Constant @f$ 2 / \sqrt(\pi) @f$. 82 static _Tp __2_sqrtpi() throw() 83 { return static_cast<_Tp>(1.1283791670955125738961589031215452L); } 84 /// Constant @f$ \sqrt(2) @f$. 85 static _Tp __sqrt2() throw() 86 { return static_cast<_Tp>(1.4142135623730950488016887242096981L); } 87 /// Constant @f$ \sqrt(3) @f$. 88 static _Tp __sqrt3() throw() 89 { return static_cast<_Tp>(1.7320508075688772935274463415058723L); } 90 /// Constant @f$ \sqrt(\pi/2) @f$. 91 static _Tp __sqrtpio2() throw() 92 { return static_cast<_Tp>(1.2533141373155002512078826424055226L); } 93 /// Constant @f$ 1 / sqrt(2) @f$. 94 static _Tp __sqrt1_2() throw() 95 { return static_cast<_Tp>(0.7071067811865475244008443621048490L); } 96 /// Constant @f$ \log(\pi) @f$. 97 static _Tp __lnpi() throw() 98 { return static_cast<_Tp>(1.1447298858494001741434273513530587L); } 99 /// Constant Euler's constant @f$ \gamma_E @f$. 100 static _Tp __gamma_e() throw() 101 { return static_cast<_Tp>(0.5772156649015328606065120900824024L); } 102 /// Constant Euler-Mascheroni @f$ e @f$ 103 static _Tp __euler() throw() 104 { return static_cast<_Tp>(2.7182818284590452353602874713526625L); } 105 }; 106 107 108 #if _GLIBCXX_USE_C99_MATH && !_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC 109 110 /// This is a wrapper for the isnan function. Otherwise, for NaN, 111 /// all comparisons result in false. If/when we build a std::isnan 112 /// out of intrinsics, this will disappear completely in favor of 113 /// std::isnan. 114 template<typename _Tp> 115 inline bool __isnan(_Tp __x) 116 { return std::isnan(__x); } 117 118 #else 119 120 template<typename _Tp> 121 inline bool __isnan(const _Tp __x) 122 { return __builtin_isnan(__x); } 123 124 template<> 125 inline bool __isnan<float>(float __x) 126 { return __builtin_isnanf(__x); } 127 128 template<> 129 inline bool __isnan<long double>(long double __x) 130 { return __builtin_isnanl(__x); } 131 132 #endif 133 } // namespace __detail 134 #if ! _GLIBCXX_USE_STD_SPEC_FUNCS && defined(_GLIBCXX_TR1_CMATH) 135 } // namespace tr1 136 #endif 137 138 _GLIBCXX_END_NAMESPACE_VERSION 139 } 140 141 #endif // _GLIBCXX_TR1_SPECIAL_FUNCTION_UTIL_H 142 143