我正在尝试使用matplotlib绘制围绕球体的磁场流线，它确实工作得很好。但是，生成的图像不是对称的，但是应该是对称的（我认为）。

这是用于生成图像的代码。请原谅，但我认为这比仅发布不起作用的代码片段要好。另外，它不是很pythonic。那是因为我从Matlab转换了它，这比我预期的要容易。

from __future__ import division
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.patches import Circle

def cart2spherical(x, y, z):
    r = np.sqrt(x**2 + y**2 + z**2)
    phi = np.arctan2(y, x)
    theta = np.arccos(z/r)
    if r == 0:
        theta = 0
    return (r, theta, phi)

def S(theta, phi):
    S = np.array([[np.sin(theta)*np.cos(phi), np.cos(theta)*np.cos(phi), -np.sin(phi)],
                  [np.sin(theta)*np.sin(phi), np.cos(theta)*np.sin(phi),  np.cos(phi)],
                  [np.cos(theta),             -np.sin(theta),             0]])
    return S

def computeB(r, theta, phi, a=1, muR=100, B0=1):
    delta = (muR - 1)/(muR + 2)
    if r > a:
        Bspherical = B0*np.array([np.cos(theta) * (1 + 2*delta*a**3 / r**3),
                                  np.sin(theta) * (delta*a**3 / r**3 - 1),
                                  0])
        B = np.dot(S(theta, phi), Bspherical)
    else:
        B = 3*B0*(muR / (muR + 2)) * np.array([0, 0, 1])
    return B

Z, X = np.mgrid[-2.5:2.5:1000j, -2.5:2.5:1000j]
Bx = np.zeros(np.shape(X))
Bz = np.zeros(np.shape(X))
Babs = np.zeros(np.shape(X))
for i in range(len(X)):
    for j in range(len(Z)):
        r, theta, phi = cart2spherical(X[0, i], 0, Z[j, 0])
        B = computeB(r, theta, phi)
        Bx[i, j], Bz[i, j] = B[0], B[2]
        Babs[i, j] = np.sqrt(B[0]**2 + B[1]**2 + B[2]**2)

fig=plt.figure()
ax=fig.add_subplot(111)

plt.streamplot(X, Z, Bx, Bz, color='k', linewidth=0.8*Babs, density=1.3,
               minlength=0.9, arrowstyle='-')
ax.add_patch(Circle((0, 0), radius=1, facecolor='none', linewidth=2))
plt.axis('equal')
plt.axis('off')
fig.savefig('streamlines.pdf', transparent=True, bbox_inches='tight', pad_inches=0)