/*Arithmetic Geometric Mean of 1 and 1/sqrt(2) Nigel_Galloway February 7th., 2012. */ #include "gmp.h" void agm (const mpf_t in1, const mpf_t in2, mpf_t out1, mpf_t out2) { mpf_add (out1, in1, in2); mpf_div_ui (out1, out1, 2); mpf_mul (out2, in1, in2); mpf_sqrt (out2, out2); } int main (void) { mpf_set_default_prec (65568); mpf_t x0, y0, resA, resB; mpf_init_set_ui (y0, 1); mpf_init_set_d (x0, 0.5); mpf_sqrt (x0, x0); mpf_init (resA); mpf_init (resB); for(int i=0; i<7; i++){ agm(x0, y0, resA, resB); agm(resA, resB, x0, y0); } gmp_printf ("%.20000Ff\n", x0); gmp_printf ("%.20000Ff\n\n", y0); return 0; }