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# fizyk20/earth.py Secret

Created Sep 5, 2018
Skrypt liczący promień Ziemi
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 #!/usr/bin/env python from mpmath import * import sys lim_d1 = (mpf(3050), mpf(3200)) lim_d2 = (mpf(12200), mpf(12800)) lim_h = (mpf(1.5), mpf(3.5)) lim_H = (mpf(69.5), mpf(73)) ratio = (mpf(50)/mpf(1180), mpf(120)/mpf(1110)) mp.dps = 100 def horizon_elev(R, h): return asin(R/(R+h)) def elev(R, src_h, distance, tgt_h): elev = atan((R+tgt_h)*sin(distance/R)/((R+src_h) - (R+tgt_h)*cos(distance/R))) if elev < 0: elev += pi return elev def angles(R, h, H, d1, d2): horiz_elev = horizon_elev(R, h) bridge_elev = elev(R, h, d2, H) island_elev = elev(R, h, d1, 0) return horiz_elev-island_elev, bridge_elev-horiz_elev def find_r_for_params(params): d1, d2, h, H, tgt_ratio = params Rmin = 2400000 Rmax = 100000000 while Rmax - Rmin > 1000: R = (Rmin + Rmax) / 2 a, b = angles(mpf(R), h, H, d1, d2) ratio = a/b if ratio < tgt_ratio: Rmin = R elif ratio >= tgt_ratio: Rmax = R return R def iter_params(): for i in range(0,32): id1 = i % 2 id2 = (i >> 1) % 2 ih = (i >> 2) % 2 iH = (i >> 3) % 2 iratio = (i >> 4) % 2 yield (lim_d1[id1], lim_d2[id2], lim_h[ih], lim_H[iH], ratio[iratio]) if __name__ == "__main__": min_radius = 1e9 max_radius = 0 for params in iter_params(): r = find_r_for_params(params) if r < min_radius: min_radius = r if r > max_radius: max_radius = r print("Min radius:", min_radius) print("Max radius:", max_radius)