// // Lol Engine - Sample math program: compute Pi // // Copyright: (c) 2005-2011 Sam Hocevar // This program is free software; you can redistribute it and/or // modify it under the terms of the Do What The Fuck You Want To // Public License, Version 2, as published by Sam Hocevar. See // http://sam.zoy.org/projects/COPYING.WTFPL for more details. // #if defined HAVE_CONFIG_H # include "config.h" #endif #include #include "core.h" using std::printf; using std::sqrt; using lol::real; int main(int argc, char **argv) { printf("Pi: "); real::R_PI().print(); printf("e: "); real::R_E().print(); printf("ln(2): "); real::R_LN2().print(); printf("sqrt(2): "); real::R_SQRT2().print(); printf("sqrt(1/2): "); real::R_SQRT1_2().print(); /* Gauss-Legendre computation of Pi -- doesn't work well at all, * probably because we use finite precision. */ real a = 1.0, b = sqrt((real)0.5), t = 0.25, p = 1.0; for (int i = 0; i < 3; i++) { real a2 = (a + b) * (real)0.5; real b2 = sqrt(a * b); real tmp = a - a2; real t2 = t - p * tmp * tmp; real p2 = p + p; a = a2; b = b2; t = t2; p = p2; } real sum = a + b; sum = sum * sum / ((real)4 * t); sum.print(); return EXIT_SUCCESS; }