diff options
Diffstat (limited to 'buch/chapters/110-elliptisch/agm/agm.cpp')
-rw-r--r-- | buch/chapters/110-elliptisch/agm/agm.cpp | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/buch/chapters/110-elliptisch/agm/agm.cpp b/buch/chapters/110-elliptisch/agm/agm.cpp new file mode 100644 index 0000000..fdb0441 --- /dev/null +++ b/buch/chapters/110-elliptisch/agm/agm.cpp @@ -0,0 +1,42 @@ +/* + * agm.cpp + * + * (c) 2022 Prof Dr Andreas Müller, OST Ostschweizer Fachhochschule + */ +#include <cstdlib> +#include <cstdio> +#include <cmath> +#include <iostream> +#include <gsl/gsl_sf_ellint.h> + + + +int main(int argc, char *argv[]) { + long double a = 1; + long double b = sqrtl(2.)/2; + if (argc >= 3) { + a = std::stod(argv[1]); + b = std::stod(argv[2]); + } + + { + long double an = a; + long double bn = b; + for (int i = 0; i < 10; i++) { + printf("%d %24.18Lf %24.18Lf %24.18Lf\n", + i, an, bn, a * M_PI / (2 * an)); + long double A = (an + bn) / 2; + bn = sqrtl(an * bn); + an = A; + } + } + + { + double k = b/a; + k = sqrt(1 - k*k); + double K = gsl_sf_ellint_Kcomp(k, GSL_PREC_DOUBLE); + printf(" %24.18f %24.18f\n", k, K); + } + + return EXIT_SUCCESS; +} |