let _ = let start = [(Base 1.0); (Base 1.0)] in let f x1 y1 x2 y2 = ((sqr x1)+.(sqr y1))-.((sqr x2)+.(sqr y2)) in let [x1_star; y1_star] = multivariate_argmin_R (fun [x1; y1] -> multivariate_max_R (fun [x2; y2] -> f x1 y1 x2 y2) start) start in let [x2_star; y2_star] = multivariate_argmax_R (fun [x2; y2] -> f x1_star y1_star x2 y2) start in [[(write_real x1_star); (write_real y1_star)]; [(write_real x2_star); (write_real y2_star)]]; 0