我一直试图找出为什么函数Momenta无法找到Name Momentum，即使我已通过括号链接它。输入所有输入后。
Number of stars: 2
Please enter The x position of the Star: 0
Please enter The y position of the Star: 0
Please enter The z position of the Star: 0
Please enter the Radius of the Star: 50
Please enter the Mass of the Star: 500000000000
Please enter the X speed of Star: 0
Please enter the Y speed of Star: 0
Please enter the Z speed of Star: 0
Please enter The x position of the Star: 500
Please enter The y position of the Star: 0
Please enter The z position of the Star: 0
Please enter the Radius of the Star: 50
Please enter the Mass of the Star: 500000000000
Please enter the X speed of Star: 0
Please enter the Y speed of Star: 0
Please enter the Z speed of Star: 0
这是我得到的错误。
Traceback（最近一次调用最后一次）：文件“C：/ Users / Benjamin Andeson / Desktop / VPython Work / Planetary Orbits Ver 6.py“，第93行 Momenta（Momentum，Mass）NameError：名称'Momentum'未定义
from visual import *
from time import clock
from random import random
# Stars interacting gravitationally
# Program uses numpy arrays for high speed computations
Nstars = int(input("Number of stars: ")) # change this to have more or fewer stars
G = 6.7e-11 # Universal gravitational constant
# Typical values
Msun = 2E30
Rsun = 2E9
vsun = 0.8*sqrt(G*Msun/Rsun)
dt = 10.0 #Reprensents the change in time
Nsteps = 0
time = clock()
Nhits = 0
Stars = []
colors = [color.red, color.green, color.blue,
color.yellow, color.cyan, color.magenta]
PositionList = []
MomentumList = []
MassList = []
RadiusList = []
def Calculations(SpeedX, SpeedY, SpeedZ, x, y, z, Mass, Radius):
px = Mass*(SpeedX)
py = Mass*(SpeedY)
pz = Mass*(SpeedZ)
PositionList.append((x,y,z))
MomentumList.append((px,py,pz))
MassList.append(Mass)
RadiusList.append(Radius)
def StarCreation(Stars,x,y,z,Radius):
Stars = Stars+[sphere(pos=(x,y,z), radius=Radius, color=colors[i % 6],
make_trail=True, interval=10)]
def DataCollection():
x = input("Please enter The x position of the Star: ")
y = input("Please enter The y position of the Star: ")
z = input("Please enter The z position of the Star: ")
Radius = input("Please enter the Radius of the Star: ")
StarCreation(Stars,x,y,z,Radius)
Mass = input("Please enter the Mass of the Star: ")
SpeedX = input("Please enter the X speed of Star: ")
SpeedY = input("Please enter the Y speed of Star: ")
SpeedZ = input("Please enter the Z speed of Star: ")
Calculations(SpeedX, SpeedY, SpeedZ, x, y, z, Mass, Radius)
def ListToArray(PositionList, MomentumList, MassList, RadiusList):
pos = array(PositionList)
Momentum = array(MomentumList)
Masses = array(MassList)
Masses.shape = (Nstars,1) # Numeric Python: (1 by Nstars) vs. (Nstars by 1)
Radii = array(RadiusList)
def Momenta(Momentum, Masses):
vcm = sum(Momentum)/sum(Masses) # velocity of center of mass
Momentum = Momentum-Masses*vcm # make total initial momentum equal zero
def Forces():
# Compute all forces on all stars
r = pos-pos[:,newaxis] # all pairs of star-to-star vectors (Where r is the Relative Position Vector
for n in range(Nstars):
r[n,n] = 1e6 # otherwise the self-forces are infinite
rmag = sqrt(sum(square(r),-1)) # star-to-star scalar distances
hit = less_equal(rmag,Radii+Radii[:,newaxis])-identity(Nstars)
hitlist = sort(nonzero(hit.flat)[0]).tolist() # 1,2 encoded as 1*Nstars+2
F = G*Mass*Mass[:,newaxis]*r/rmag[:,:,newaxis]**3 # all force pairs
def UpdateMomentaPositions(Momentum, pos, Masses):
Momentum = Momentum+sum(F,1)*dt
pos = pos+(Momentum/Masses)*dt
def UpdateDisplay(pos):
Stars[i].pos = pos[i]
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ACUTAL PROGRAM ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#
for i in range(Nstars):
DataCollection()
ListToArray(PositionList, MomentumList, MassList, RadiusList)
Momenta(Momentum, Masses)
while True:
rate(100) # No more than 100 loops per second on fast computers
Forces(pos, Radii, Mass) # Computes all the forces between masses
for n in range(NStars):
F[n,n] = 0 # No self forces
UpdateMomentaPositions(Momentum,pos,Mass) # Updates the Momentum and Positions of Stars
for i in range(Nstars):
UpdateDisplay(pos) # Updates the 3D displays position of Masses
#~~~~~~~~~~~~~~~~~~~~~~~~~~~ NEEDS TO BE FIXED ~~~~~~~~~~~~~~~~~~~~~~~~~~~#
# If any collisions took place, merge those stars
# for ij in hitlist:
# i, j = divmod(ij,Nstars) # decode star pair
# if not Stars[i].visible: continue
# if not Stars[j].visible: continue
# m[i] is a one-element list, e.g. [6e30]
# m[i,0] is an ordinary number, e.g. 6e30
# newpos = (pos[i]*m[i,0]+pos[j]*m[j,0])/(m[i,0]+m[j,0])
# newmass = m[i,0]+m[j,0]
# newp = p[i]+p[j]
# newradius = Rsun*((newmass/Msun)**(1./3.))
# iset, jset = i, j
# if radius[j] > radius[i]:
# iset, jset = j, i
# Stars[iset].radius = newradius
# m[iset,0] = newmass
# pos[iset] = newpos
# p[iset] = newp
# Stars[jset].trail_object.visible = False
# Stars[jset].visible = 0
# p[jset] = vector(0,0,0)
# m[jset,0] = Msun*1E-30 # give it a tiny mass
# Nhits = Nhits+1
# pos[jset] = (10.*L*Nhits, 0, 0) # put it far away
# Nsteps += 1