Моделирование движения тел в гравитационном поле на python (scipy.odeint, matplotlib, numpy)

from scipy.integrate import odeint
import scipy.constants as constants
import numpy as np
import matplotlib.pyplot as plt
 
M = 1.989 * (10 ** 30)
G = constants.G
alpha = 30
alpha0 = (alpha / 180) * np.pi
v00 = 0.7  # km/s
v0 = v00 * 1000  # m/s
 
 
def dqdt(q, t):
    x = q[0]
    y = q[2]
    ax = - G * M * (x / ((x ** 2 + y ** 2) ** 1.5))
    ay = - G * M * (y / ((x ** 2 + y ** 2) ** 1.5))
    return [q[1], ax, q[3], ay]
 
 
vx0 = v0 * np.cos(alpha0)
vy0 = v0 * np.sin(alpha0)
x0 = -1.5 * (10 ** 11)
y0 = 0 * (10 ** 11)
q0 = [x0, vx0, y0, vy0]
 
N = 1000000
t = np.linspace(0.0, 100000000000.0, N)
 
pos = odeint(dqdt, q0, t)
 
x1 = pos[:, 0]
y1 = pos[:, 2]
 
plt.plot(x1, y1, 0, 0, 'ro')
plt.ylabel('y')
plt.xlabel('x')
plt.grid(True)
plt.show()

for n=0 to Nmass
for m=0 to Nmass
 if m==n continue for
dx=x(n)-x(m)
dy=y(n)-y(m)
R=sqr(DX*DX+DY*DY) 
   f=6.67e-11*[S]mass(n)[/S]*mass(m))/(R*R)
    afx=f*dx/R/[S]mass(n)[/S]
    afy=f*dy/R/[S]mass(n)[/S]
 
   vx(n)=vx(n)+afx*dt
    vy(n)=vy(n)+afy*dt
 
    x(n)=x(n)+vx(n)*dt
    y(n)=y(n)+vy(n)*dt
 next next