试图让两个质量彼此绕轨道运行......出现奇怪的错误

Question

基本上，我已经创建了质量，给了它们一些速度和动量，并且我试图利用重力使它们彼此绕轨道（围绕它们的质心）。

from visual import *

earth = sphere(radius = 100000000)
newPlanet = sphere(pos = (3.84403*10**8, 0, 0), radius = 10000000)

earth.velocity = vector(0, 100, 0)
newPlanet.velocity = vector(0, 100, 0)

earth.mass = 2*10**30
newPlanet.mass = 1*10**30

earth.p = vector(0, earth.mass*earth.velocity, 0)
newPlanet.p = vector(0, newPlanet.mass*newPlanet.velocity, 0)

dt = 1000
r = newPlanet.pos.x
T = 1.296*10**6
G = 6.673*10**-11

while 1:
    Fnet = G*((earth.mass*newPlanet.mass)/r**2)

    earth.p += Fnet*dt
    newPlanet.p += Fnet*dt

    earth.velocity += (earth.p/earth.mass)*dt
    newPlanet.velocity += (newPlanet.p/newPlanet.mass)*dt

    earth.pos += earth.velocity*dt
    newPlanet.pos += newPlanet.velocity*dt

    t += 1

    rate(100)

这是我收到的错误：

Traceback (most recent call last):
  File "Untitled", line 12
    earth.p = vector(0, earth.mass*earth.velocity, 0)
Boost.Python.ArgumentError: Python argument types in
    vector.__init__(vector, int, vector, int)
did not match C++ signature:
    __init__(struct _object *, class cvisual::vector)
    __init__(struct _object *)
    __init__(struct _object *, double)
    __init__(struct _object *, double, double)
    __init__(struct _object *, double, double, double)

Answer 1

矢量采用三个数字作为参数，如 vpython 文档此处所示

在您的作业中 earth .p = vector(0, Earth.mass*earth.velocity, 0), earth.mass*earth.velocity 是一个向量，如下typeof(earth.mass*earth.velocity) 将指示而不是预期的数字。

因此出现错误消息，您确定您的意思不是

earth.p = vector(0, Earth.mass*mag(earth.velocity), 0)

或 earth.p = vector (0, Earth.mass*earth.velocity.y, 0) 代替。