libstdc++-v3/include/tr1/special_function_util.h

   1 // Special functions -*- C++ -*-
   2
   3 // Copyright (C) 2006, 2009, 2010
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // Under Section 7 of GPL version 3, you are granted additional
  18 // permissions described in the GCC Runtime Library Exception, version
  19 // 3.1, as published by the Free Software Foundation.
  20
  21 // You should have received a copy of the GNU General Public License and
  22 // a copy of the GCC Runtime Library Exception along with this program;
  23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 // <http://www.gnu.org/licenses/>.
  25
  26 /** @file tr1/special_function_util.h
  27  *  This is an internal header file, included by other library headers.
  28  *  Do not attempt to use it directly. @headername{tr1/cmath}
  29  */
  30
  31 //
  32 // ISO C++ 14882 TR1: 5.2  Special functions
  33 //
  34
  35 // Written by Edward Smith-Rowland based on numerous mathematics books.
  36
  37 #ifndef _GLIBCXX_TR1_SPECIAL_FUNCTION_UTIL_H
  38 #define _GLIBCXX_TR1_SPECIAL_FUNCTION_UTIL_H 1
  39
  40 namespace std _GLIBCXX_VISIBILITY(default)
  41 {
  42 namespace tr1
  43 {
  44   namespace __detail
  45   {
  46   _GLIBCXX_BEGIN_NAMESPACE_VERSION
  47
  48     /// A class to encapsulate type dependent floating point
  49     /// constants.  Not everything will be able to be expressed as
  50     /// type logic.
  51     template<typename _Tp>
  52     struct __floating_point_constant
  53     {
  54       static const _Tp __value;
  55     };
  56
  57
  58     /// A structure for numeric constants.
  59     template<typename _Tp>
  60       struct __numeric_constants
  61       {
  62         ///  Constant @f$ \pi @f$.
  63         static _Tp __pi() throw()
  64         { return static_cast<_Tp>(3.1415926535897932384626433832795029L); }
  65         ///  Constant @f$ \pi / 2 @f$.
  66         static _Tp __pi_2() throw()
  67         { return static_cast<_Tp>(1.5707963267948966192313216916397514L); }
  68         ///  Constant @f$ \pi / 3 @f$.
  69         static _Tp __pi_3() throw()
  70         { return static_cast<_Tp>(1.0471975511965977461542144610931676L); }
  71         ///  Constant @f$ \pi / 4 @f$.
  72         static _Tp __pi_4() throw()
  73         { return static_cast<_Tp>(0.7853981633974483096156608458198757L); }
  74         ///  Constant @f$ 1 / \pi @f$.
  75         static _Tp __1_pi() throw()
  76         { return static_cast<_Tp>(0.3183098861837906715377675267450287L); }
  77         ///  Constant @f$ 2 / \sqrt(\pi) @f$.
  78         static _Tp __2_sqrtpi() throw()
  79         { return static_cast<_Tp>(1.1283791670955125738961589031215452L); }
  80         ///  Constant @f$ \sqrt(2) @f$.
  81         static _Tp __sqrt2() throw()
  82         { return static_cast<_Tp>(1.4142135623730950488016887242096981L); }
  83         ///  Constant @f$ \sqrt(3) @f$.
  84         static _Tp __sqrt3() throw()
  85         { return static_cast<_Tp>(1.7320508075688772935274463415058723L); }
  86         ///  Constant @f$ \sqrt(\pi/2) @f$.
  87         static _Tp __sqrtpio2() throw()
  88         { return static_cast<_Tp>(1.2533141373155002512078826424055226L); }
  89         ///  Constant @f$ 1 / sqrt(2) @f$.
  90         static _Tp __sqrt1_2() throw()
  91         { return static_cast<_Tp>(0.7071067811865475244008443621048490L); }
  92         ///  Constant @f$ \log(\pi) @f$.
  93         static _Tp __lnpi() throw()
  94         { return static_cast<_Tp>(1.1447298858494001741434273513530587L); }
  95         ///  Constant Euler's constant @f$ \gamma_E @f$.
  96         static _Tp __gamma_e() throw()
  97         { return static_cast<_Tp>(0.5772156649015328606065120900824024L); }
  98         ///  Constant Euler-Mascheroni @f$ e @f$
  99         static _Tp __euler() throw()
 100         { return static_cast<_Tp>(2.7182818284590452353602874713526625L); }
 101       };
 102
 103
 104 #if _GLIBCXX_USE_C99_MATH && !_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC
 105
 106     /// This is a wrapper for the isnan function. Otherwise, for NaN,
 107     /// all comparisons result in false. If/when we build a std::isnan
 108     /// out of intrinsics, this will disappear completely in favor of
 109     /// std::isnan.
 110     template<typename _Tp>
 111     inline bool __isnan(const _Tp __x)
 112     {
 113       return std::isnan(__x);
 114     }
 115
 116 #else
 117
 118     template<typename _Tp>
 119     inline bool __isnan(const _Tp __x)
 120     {
 121       return __builtin_isnan(__x);
 122     }
 123
 124     template<>
 125     inline bool __isnan<float>(const float __x)
 126     {
 127       return __builtin_isnanf(__x);
 128     }
 129
 130     template<>
 131     inline bool __isnan<long double>(const long double __x)
 132     {
 133       return __builtin_isnanl(__x);
 134     }
 135
 136 #endif
 137
 138   _GLIBCXX_END_NAMESPACE_VERSION
 139   } // namespace __detail
 140 }
 141 }
 142
 143 #endif // _GLIBCXX_TR1_SPECIAL_FUNCTION_UTIL_H
 144