6 // this is so very darn long so it can easily be changed to double
7 constexpr float PI = 3.141592653589793238462643383279502884;
8 constexpr float PI2 = 2 * PI;
10 // gravitational constant in m^3 kg^-1 s^-2 (= N m^2 kg^-2) (for use with F = G ((m1 m2) / r^2)
11 constexpr float G = 6.67384e-11;
14 constexpr int sigma(T v) {
15 return v > 0 ? 1 : (v < 0 ? -1 : 0);