我之前已经发布过类似的问题，但是，我想我可能误解了我的问题，所以我可以在这里发布我的原始代码，并寻找有人可以帮助我，我现在真的陷入了困境..非常感谢。
from numpy import *
import math as M
#initial condition All in SI unit
G=6.673*10**-11 #Gravitational constant
ms=1.9889*10**30 #mass of the sun
me=5.9742*10**24 #mass of the earth
dt=10 #time step
#Creat arrays
vs=array([[0,0,0]]) #1st element stand for x component of V of earth
ve=array([[29770,0,0]])
rs=array([[0,0,0]])
re=array([[0,1.4960*10**11,0]])
#First update velocity in order to start leapfrog approximation
fs=-G*ms*me*((rs-re)/(M.sqrt((rs-re)[0][0]**2+(rs-re)[0][1]**2+(rs-re)[0][2]**2))**3)
fe=-fs
vs=vs+fs*dt/ms
ve=ve+fe*dt/me
n=input('please enter the number of timestep you want it evolve:')
#update force
def force(n,ms,me,rs,re,G):
rs,re=update_r(rs,re,n,dt)
fs=-G*ms*me*((rs-re)/(M.sqrt((rs-re)[0][0]**2+(rs-re)[0][1]**2+(rs-re)[0][2]**2))**3)
fe=-fs
return fs,fe
#update velocities
def update_v(n,vs,ve,ms,me,dt,fs,fe):
fs,fe=force(n,ms,me,rs,re,G)
i=arange(n)
vs=vs+fs[:]*i[:,newaxis]*dt/ms
ve=ve+fe[:]*i[:,newaxis]*dt/me
return vs,ve
#update position
def update_r(rs,re,n,dt):
vs,ve=update_v(n,vs,ve,ms,me,dt,fs,fe)
i=arange(n)
rs=rs+vs[:]*i[:,newaxis]*dt
re=re+ve[:]*i[:,newaxis]*dt
return rs,re
#there is start position,v,r,f all have initial arrays(when n=0).
#then it should calculate f(n=1) then use this to update v(n=0)
#to v(n=1),then use v(n=1) update r(n=0) to r(n=1),then use r(n=1)
#update f(n=1) to f(n=2)....and so on until finish n.but this code seems doesnt do this,,how can I make it? –
当我调用force python时给出：
please enter the number of timestep you want it evolve:4Traceback (most recent call last):
File "<pyshell#391>", line 1, in <module>
force(n,ms,me,rs,re,G)
File "/Users/Code.py", line 24, in force
rs,re=update_r(rs,re,n,dt)
File "/Users/Code.py", line 39, in update_r
vs,ve=update_v(n,vs,ve,ms,me,dt,fs,fe)
UnboundLocalError: local variable 'vs' referenced before assignment
谁能给我一些建议吗？谢谢......
