1 // Special functions -*- C++ -*- 2 3 // Copyright (C) 2006-2013 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 namespace tr1 42 { 43 namespace __detail 44 { 45 _GLIBCXX_BEGIN_NAMESPACE_VERSION 46 47 /// A class to encapsulate type dependent floating point 48 /// constants. Not everything will be able to be expressed as 49 /// type logic. 50 template<typename _Tp> 51 struct __floating_point_constant 52 { 53 static const _Tp __value; 54 }; 55 56 57 /// A structure for numeric constants. 58 template<typename _Tp> 59 struct __numeric_constants 60 { 61 /// Constant @f$ \pi @f$. 62 static _Tp __pi() throw() 63 { return static_cast<_Tp>(3.1415926535897932384626433832795029L); } 64 /// Constant @f$ \pi / 2 @f$. 65 static _Tp __pi_2() throw() 66 { return static_cast<_Tp>(1.5707963267948966192313216916397514L); } 67 /// Constant @f$ \pi / 3 @f$. 68 static _Tp __pi_3() throw() 69 { return static_cast<_Tp>(1.0471975511965977461542144610931676L); } 70 /// Constant @f$ \pi / 4 @f$. 71 static _Tp __pi_4() throw() 72 { return static_cast<_Tp>(0.7853981633974483096156608458198757L); } 73 /// Constant @f$ 1 / \pi @f$. 74 static _Tp __1_pi() throw() 75 { return static_cast<_Tp>(0.3183098861837906715377675267450287L); } 76 /// Constant @f$ 2 / \sqrt(\pi) @f$. 77 static _Tp __2_sqrtpi() throw() 78 { return static_cast<_Tp>(1.1283791670955125738961589031215452L); } 79 /// Constant @f$ \sqrt(2) @f$. 80 static _Tp __sqrt2() throw() 81 { return static_cast<_Tp>(1.4142135623730950488016887242096981L); } 82 /// Constant @f$ \sqrt(3) @f$. 83 static _Tp __sqrt3() throw() 84 { return static_cast<_Tp>(1.7320508075688772935274463415058723L); } 85 /// Constant @f$ \sqrt(\pi/2) @f$. 86 static _Tp __sqrtpio2() throw() 87 { return static_cast<_Tp>(1.2533141373155002512078826424055226L); } 88 /// Constant @f$ 1 / sqrt(2) @f$. 89 static _Tp __sqrt1_2() throw() 90 { return static_cast<_Tp>(0.7071067811865475244008443621048490L); } 91 /// Constant @f$ \log(\pi) @f$. 92 static _Tp __lnpi() throw() 93 { return static_cast<_Tp>(1.1447298858494001741434273513530587L); } 94 /// Constant Euler's constant @f$ \gamma_E @f$. 95 static _Tp __gamma_e() throw() 96 { return static_cast<_Tp>(0.5772156649015328606065120900824024L); } 97 /// Constant Euler-Mascheroni @f$ e @f$ 98 static _Tp __euler() throw() 99 { return static_cast<_Tp>(2.7182818284590452353602874713526625L); } 100 }; 101 102 103 #if _GLIBCXX_USE_C99_MATH && !_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC 104 105 /// This is a wrapper for the isnan function. Otherwise, for NaN, 106 /// all comparisons result in false. If/when we build a std::isnan 107 /// out of intrinsics, this will disappear completely in favor of 108 /// std::isnan. 109 template<typename _Tp> 110 inline bool __isnan(_Tp __x) 111 { return std::isnan(__x); } 112 113 #else 114 115 template<typename _Tp> 116 inline bool __isnan(const _Tp __x) 117 { return __builtin_isnan(__x); } 118 119 template<> 120 inline bool __isnan<float>(float __x) 121 { return __builtin_isnanf(__x); } 122 123 template<> 124 inline bool __isnan<long double>(long double __x) 125 { return __builtin_isnanl(__x); } 126 127 #endif 128 129 _GLIBCXX_END_NAMESPACE_VERSION 130 } // namespace __detail 131 } 132 } 133 134 #endif // _GLIBCXX_TR1_SPECIAL_FUNCTION_UTIL_H 135 136
