SciPy ODE 求解器忽略函数

Question

我正在尝试让 Scipy 的 ODE 求解器求解洛伦兹力微分方程。它不能用 B 场分量正确求解方程，因为无论我做多大的 E 场，它都会完全忽略它（这也是我知道它忽略它的原因）。为什么是这样？我也已经尝试过修改 E-field 功能上的标志。

代码：

import numpy as np

import pylab

from scipy.integrate import odeint

import matplotlib.pyplot as plt

#import random

import mpl_toolkits.mplot3d.axes3d as p3

#Mirroring Angle to Recreate

ThetaMirror = 40

TStep = 1

TFinal = 10

P0 = [0.,0.02,0.]

V0 = [1,0,0]

t = np.linspace(0,TFinal,num=(TFinal/TStep))

#Physical/Natural Constants

q_e = -1

m_e = 1

QeMe = q_e/m_e

u0 = 1

#Math

ICs = np.concatenate((P0,V0),axis=0)

def BField(x,y,z):

    Bx = 0

    By = 0

    Bz = 1

    BVec = np.array([Bx,By,Bz])

    return BVec

def EField(x,y,z):

    Ex = 0

    Ey = 0

    Ez = 2.8E8*z**4

    EVec = np.array([Ex,Ey,Ez])

    return EVec

def LorentzForce(PosVel,t,Constants):

    x,y,z,vx,vy,vz = PosVel

    Ex,Ey,Ez,Bx,By,Bz,QeMe = Constants

    EFInput = np.array([Ex,Ey,Ez])

    BFInput = np.array([Bx,By,Bz])

    VelInput = np.array([vx,vy,vz])

    Accel = QeMe * (EFInput + np.cross(VelInput, BFInput))   

    LFEqs = np.concatenate((VelInput, Accel), axis = 0)

    return LFEqs

Ex,Ey,Ez = EField(P0[0],P0[1],P0[2])

Bx,By,Bz = BField(P0[0],P0[1],P0[2])

#Ex = Ey = Ez = 0

AllConstantInputs = [Ex,Ey,Ez,Bx,By,Bz,QeMe]

ParticleTrajectory = odeint(LorentzForce, ICs, t, args=(AllConstantInputs,))

print(ParticleTrajectory)

print(Bz)

fig = plt.figure()

particleplot = fig.add_subplot(111,projection='3d')

particleplot.plot(ParticleTrajectory[:, 0],ParticleTrajectory[:, 1],ParticleTrajectory[:, 2],'b')

particleplot.set_xlabel('x axis')

particleplot.set_ylabel('y axis')

particleplot.set_zlabel('z axis')

particleplot.legend(loc='best')

particleplot.grid()

plt.show()

Answer 1

你定义P0[2] = 0.. 电场函数计算Ez = 2.8E8*z**4。因此，python 没有忽略 E-field 函数，您自己将其 z 分量置零：z = P0[2] = 0.