在numpy上绘制2D高斯

Question

I am a new in numpy and I try to practice the basic operations. Here is a code to plot a 2D gaussian distribution. I have an error in matplotlib. How can I fix that?

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D

X,Y=np.meshgrid(np.linspace(-1,1,10),np.linspace(-1,1,10));
mu,sigma=0,1; #suppose that mux=muy=mu=0 and sigmax=sigmay=sigma
G=np.exp(-((X-mu)**2+(Y-mu)**2)/2.0*sigma**2)
print G
fig=plt.figure();
ax=fig.add_subplot(111,projection='3d')
surf=ax.plot_surface(X,Y,G,c='red')
plt.show()

I have this error
File "/Library/Python/2.7/site-packages/mpl_toolkits/mplot3d/__init__.py", line 4, in from matplotlib.externals import six ImportError: No module named externals

Answer 1

Because with my versions it works so I suspect you need to upgrade mpl_toolkits (and/or matplotlib ).

It seems like matplotlib dropped support for older Python versions (and you have a more recent version) and therefore doesn't need an externals submodule anymore. But you didn't update mpl_toolkits which still thinks matplotlib has this submodule. And therefore you get this Error.