代码：
import matplotlib.pyplot as plt
import numpy as np
def f(x, y):
return (1 - x / 2 + X ** 3) * np.exp(-x ** 2 - y ** 2)
n = 256
x = np.linspace(-3, 3, n)
y = np.linspace(-3, 3, n)
X, Y = np.meshgrid(x, y) # 网格输入值
# use plt.contour to filling contours
# X,Yand value for (X,Y)point
plt.contourf(X, Y, f(X, Y), 8,
alpha=0.75, cmap=plt.cm.hot)
# use plt.contour to add contourlines
C = plt.contour(X, Y, f(X, Y), 9, color='balck', linewidth=.5)
# adding label
plt.clabel(C, inlines=True)
plt.xticks(())
plt.yticks(())
plt.show()
运行结果：
