Dogcows Code - chaz/yoink/blob - src/Moof/cml/constants.h

   1 /* -*- C++ -*- ------------------------------------------------------------
   2
   3 Copyright (c) 2007 Jesse Anders and Demian Nave http://cmldev.net/
   4
   5 The Configurable Math Library (CML) is distributed under the terms of the
   6 Boost Software License, v1.0 (see cml/LICENSE for details).
   7
   8  *-----------------------------------------------------------------------*/
   9 /** @file
  10  *  @brief Useful constants.
  11  */
  12
  13 #ifndef cml_constants_h
  14 #define cml_constants_h
  15
  16 #include <cmath>
  17
  18 #if !defined(M_PI)
  19 #define M_PI 3.14159265358979323846264338327950288
  20 #endif
  21
  22 #if !defined(M_SQRT2)
  23 #define M_SQRT2 1.41421356237309504880168872420969808
  24 #endif
  25
  26 #if !defined(M_E)
  27 #define M_E 2.71828182845904523536028747135266250
  28 #endif
  29
  30 namespace cml {
  31
  32 #if 1
  33
  34 /** Templated constants struct.
  35  *
  36  * Either float or double can be used.
  37  */
  38 template<typename Float>
  39 struct constants {
  40     static Float pi()           { return M_PI;                             }
  41     static Float two_pi()       { return 2.*M_PI;                          }
  42     static Float inv_pi()       { return 1./M_PI;                          }
  43     static Float inv_two_pi()   { return 1./(2.*M_PI);                     }
  44     static Float pi_over_2()    { return M_PI/2.;                          }
  45     static Float pi_over_4()    { return M_PI/4.;                          }
  46     static Float deg_per_rad()  { return 180./M_PI;                        }
  47     static Float rad_per_deg()  { return M_PI/180.;                        }
  48     static Float sqrt_2()       { return M_SQRT2;                          }
  49     static Float sqrt_3()       { return 1.732050807568877293527446341505; }
  50     static Float sqrt_5()       { return 2.236067977499789696409173668731; }
  51     static Float sqrt_6()       { return 2.449489742783178098197284074705; }
  52     static Float e()            { return M_E;                              }
  53 };
  54
  55 #else
  56
  57 /* XXX This version requires an explicit instantiation of *every* constant
  58  * below, e.g.:
  59  *
  60  * template<typename F> const F cml::constants<F>::pi;
  61  */
  62 /** Templated constants struct.
  63  *
  64  * Either float or double can be used.
  65  */
  66 template<typename Float>
  67 struct constants {
  68     static const Float pi = M_PI;
  69     static const Float two_pi = 2.*M_PI;
  70     static const Float inv_pi = 1./M_PI;                /* 1/pi */
  71     static const Float inv_two_pi = 1./(2.*M_PI);       /* 1/(2*pi) */
  72     static const Float pi_over_2 = M_PI/2.;             /* pi/2 */
  73     static const Float pi_over_4 = M_PI/4.;             /* pi/4 */
  74     static const Float deg_per_rad = 180./M_PI;
  75     static const Float rad_per_deg = M_PI/180.;
  76     static const Float sqrt_2 = M_SQRT2;
  77     static const Float sqrt_3 = 1.73205080756887729352744634150587237;
  78     static const Float sqrt_5 = 2.23606797749978969640917366873127624;
  79     static const Float sqrt_6 = 2.44948974278317809819728407470589139;
  80     static const Float e = M_E;
  81 };
  82
  83 #endif
  84
  85 } // namespace cml
  86
  87 #endif