--- /dev/null
+/* -*- C++ -*- ------------------------------------------------------------
+
+Copyright (c) 2007 Jesse Anders and Demian Nave http://cmldev.net/
+
+The Configurable Math Library (CML) is distributed under the terms of the
+Boost Software License, v1.0 (see cml/LICENSE for details).
+
+ *-----------------------------------------------------------------------*/
+/** @file
+ * @brief Useful constants.
+ */
+
+#ifndef cml_constants_h
+#define cml_constants_h
+
+#include <cmath>
+
+#if !defined(M_PI)
+#define M_PI 3.14159265358979323846264338327950288
+#endif
+
+#if !defined(M_SQRT2)
+#define M_SQRT2 1.41421356237309504880168872420969808
+#endif
+
+#if !defined(M_E)
+#define M_E 2.71828182845904523536028747135266250
+#endif
+
+namespace cml {
+
+#if 1
+
+/** Templated constants struct.
+ *
+ * Either float or double can be used.
+ */
+template<typename Float>
+struct constants {
+ static Float pi() { return Float(M_PI); }
+ static Float two_pi() { return Float(2.*M_PI); }
+ static Float inv_pi() { return Float(1./M_PI); }
+ static Float inv_two_pi() { return Float(1./(2.*M_PI)); }
+ static Float pi_over_2() { return Float(M_PI/2.); }
+ static Float pi_over_4() { return Float(M_PI/4.); }
+ static Float deg_per_rad() { return Float(180./M_PI); }
+ static Float rad_per_deg() { return Float(M_PI/180.); }
+
+ static Float sqrt_2() { return Float(M_SQRT2); }
+ static Float sqrt_3() { return Float(1.732050807568877293527446341505); }
+ static Float sqrt_5() { return Float(2.236067977499789696409173668731); }
+ static Float sqrt_6() { return Float(2.449489742783178098197284074705); }
+
+ static Float e() { return Float(M_E); }
+};
+
+#else
+
+/* XXX This version requires an explicit instantiation of *every* constant
+ * below, e.g.:
+ *
+ * template<typename F> const F cml::constants<F>::pi;
+ */
+/** Templated constants struct.
+ *
+ * Either float or double can be used.
+ */
+template<typename Float>
+struct constants {
+ static const Float pi = M_PI;
+ static const Float two_pi = 2.*M_PI;
+ static const Float inv_pi = 1./M_PI; /* 1/pi */
+ static const Float inv_two_pi = 1./(2.*M_PI); /* 1/(2*pi) */
+ static const Float pi_over_2 = M_PI/2.; /* pi/2 */
+ static const Float pi_over_4 = M_PI/4.; /* pi/4 */
+ static const Float deg_per_rad = 180./M_PI;
+ static const Float rad_per_deg = M_PI/180.;
+ static const Float sqrt_2 = M_SQRT2;
+ static const Float sqrt_3 = 1.73205080756887729352744634150587237;
+ static const Float sqrt_5 = 2.23606797749978969640917366873127624;
+ static const Float sqrt_6 = 2.44948974278317809819728407470589139;
+ static const Float e = M_E;
+};
+
+#endif
+
+} // namespace cml
+
+#endif