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 Float(M_PI); }
  41     static Float two_pi()      { return Float(2.*M_PI); }
  42     static Float inv_pi()      { return Float(1./M_PI); }
  43     static Float inv_two_pi()  { return Float(1./(2.*M_PI)); }
  44     static Float pi_over_2()   { return Float(M_PI/2.); }
  45     static Float pi_over_4()   { return Float(M_PI/4.); }
  46     static Float deg_per_rad() { return Float(180./M_PI); }
  47     static Float rad_per_deg() { return Float(M_PI/180.); }
  48
  49     static Float sqrt_2() { return Float(M_SQRT2); }
  50     static Float sqrt_3() { return Float(1.732050807568877293527446341505); }
  51     static Float sqrt_5() { return Float(2.236067977499789696409173668731); }
  52     static Float sqrt_6() { return Float(2.449489742783178098197284074705); }
  53
  54     static Float e() { return Float(M_E); }
  55 };
  56
  57 #else
  58
  59 /* XXX This version requires an explicit instantiation of *every* constant
  60  * below, e.g.:
  61  *
  62  * template<typename F> const F cml::constants<F>::pi;
  63  */
  64 /** Templated constants struct.
  65  *
  66  * Either float or double can be used.
  67  */
  68 template<typename Float>
  69 struct constants {
  70     static const Float pi = M_PI;
  71     static const Float two_pi = 2.*M_PI;
  72     static const Float inv_pi = 1./M_PI;                /* 1/pi */
  73     static const Float inv_two_pi = 1./(2.*M_PI);       /* 1/(2*pi) */
  74     static const Float pi_over_2 = M_PI/2.;             /* pi/2 */
  75     static const Float pi_over_4 = M_PI/4.;             /* pi/4 */
  76     static const Float deg_per_rad = 180./M_PI;
  77     static const Float rad_per_deg = M_PI/180.;
  78     static const Float sqrt_2 = M_SQRT2;
  79     static const Float sqrt_3 = 1.73205080756887729352744634150587237;
  80     static const Float sqrt_5 = 2.23606797749978969640917366873127624;
  81     static const Float sqrt_6 = 2.44948974278317809819728407470589139;
  82     static const Float e = M_E;
  83 };
  84
  85 #endif
  86
  87 } // namespace cml
  88
  89 #endif