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Prueba del motor (code)
Code written by the AI agents of “Prueba del motor”. Each agent works on its own branch; main follows the lead agent.
Commitsmain.pyAdded+69−0
RK4 quadratic-drag projectile simulation with ground-crossing interpolation
Lasques agent 1 (lead, iteration 1) · Oct 24, 2026 · 015c4746fa981e44d36f672c8d164236822405c4
1 file changed
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| 1 | """RK4 simulation of 2D projectile with quadratic drag a = -g y - (k/m)|v|v.""" | |
| 2 | import numpy as np | |
| 3 | import lasques | |
| 4 | import matplotlib | |
| 5 | matplotlib.use("Agg") | |
| 6 | import matplotlib.pyplot as plt | |
| 7 | ||
| 8 | p = lasques.params() | |
| 9 | v0 = float(p.get("v0", 30.0)) | |
| 10 | angle_deg = float(p.get("angle_deg", 45.0)) | |
| 11 | km = float(p.get("km", 0.0)) | |
| 12 | dt = float(p.get("dt", 1e-3)) | |
| 13 | g = 9.81 | |
| 14 | ||
| 15 | th = np.radians(angle_deg) | |
| 16 | state = np.array([0.0, 0.0, v0*np.cos(th), v0*np.sin(th)]) | |
| 17 | ||
| 18 | def deriv(s): | |
| 19 | x, y, vx, vy = s | |
| 20 | sp = np.hypot(vx, vy) | |
| 21 | return np.array([vx, vy, -km*sp*vx, -g - km*sp*vy]) | |
| 22 | ||
| 23 | traj = [state.copy()] | |
| 24 | t = 0.0 | |
| 25 | max_steps = 2_000_000 | |
| 26 | for i in range(max_steps): | |
| 27 | k1 = deriv(state) | |
| 28 | k2 = deriv(state + 0.5*dt*k1) | |
| 29 | k3 = deriv(state + 0.5*dt*k2) | |
| 30 | k4 = deriv(state + dt*k3) | |
| 31 | new = state + dt/6*(k1 + 2*k2 + 2*k3 + k4) | |
| 32 | # detect ground crossing between state and new | |
| 33 | if new[1] < 0: | |
| 34 | # linear interpolation for range | |
| 35 | f = state[1] / (state[1] - new[1]) | |
| 36 | x_land = state[0] + f*(new[0]-state[0]) | |
| 37 | t_land = t + f*dt | |
| 38 | state = new | |
| 39 | traj.append(new) | |
| 40 | break | |
| 41 | state = new | |
| 42 | traj.append(new) | |
| 43 | t += dt | |
| 44 | ||
| 45 | traj = np.array(traj) | |
| 46 | range_m = x_land | |
| 47 | apex = traj[:,1].max() | |
| 48 | R_analytic_no_drag = v0**2*np.sin(2*th)/g | |
| 49 | ||
| 50 | lasques.set_metrics({"range_m": range_m, "flight_time_s": t_land, | |
| 51 | "apex_m": apex, "km": km, "dt": dt, | |
| 52 | "R_analytic_nodrag": R_analytic_no_drag}) | |
| 53 | ||
| 54 | if km == 0: | |
| 55 | rel_err = abs(range_m - R_analytic_no_drag)/R_analytic_no_drag | |
| 56 | lasques.set_metrics({"nodrag_rel_err": rel_err}) | |
| 57 | lasques.log_metric("nodrag_rel_err", rel_err) | |
| 58 | lasques.log_metric("range", range_m) | |
| 59 | lasques.save_table(traj[::max(1, len(traj)//2000), :], "trajectory") | |
| 60 | ||
| 61 | fig, ax = plt.subplots(figsize=(7,4)) | |
| 62 | ax.plot(traj[:,0], traj[:,1], label=f"k/m={km}") | |
| 63 | ax.set_xlabel("x (m)"); ax.set_ylabel("y (m)") | |
| 64 | ax.set_title(f"Projectile, v0={v0} m/s, angle={angle_deg} deg, k/m={km}, dt={dt}") | |
| 65 | ax.legend(); ax.grid(True) | |
| 66 | lasques.save_figure(fig, f"traj_km{km}_dt{dt}") | |
| 67 | ||
| 68 | lasques.summary(f"k/m={km}, dt={dt}: range={range_m:.4f} m, apex={apex:.3f} m, flight time={t_land:.3f} s") | |
| 69 | print(f"km={km} dt={dt} range={range_m:.5f} apex={apex:.4f} t={t_land:.4f}") | |