绘制等高线

import matplotlib.pyplot as plt
import numpy as np

# 定义等高线高度函数
def f(x, y):
    return (1 - x / 2 + x ** 5 + y ** 3) * np.exp(- x ** 2 - y ** 2)
    #return x**2+y**2
# 数据数目
n = 300
# 定义x, y
x = np.linspace(-3, 3, n)
y = np.linspace(-3, 3, n)

# 生成网格数据
X, Y = np.meshgrid(x, y)


# 填充等高线的颜色, 8是等高线分为几部分
plt.contourf(X, Y, f(X, Y), 8, alpha = 0.75, cmap = plt.cm.RdBu)
# 绘制等高线
C = plt.contour(X, Y, f(X, Y),8, colors = 'black', linewidth = 0.5)
# 绘制等高线数据
plt.clabel(C, inline = True, fontsize = 10)

# 去除坐标轴
# plt.xticks(())
#plt.yticks(())
plt.show()

RdBu Colormap可以参考http://matplotlib.org/users/colormaps.html

上图函数三维图像

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

def f(x, y):
    return (1 - x / 2 + x ** 5 + y ** 3) * np.exp(- x ** 2 - y ** 2)
fig = plt.figure()  
ax = Axes3D(fig)  
X = np.arange(-4, 4, 0.25)  
Y = np.arange(-4, 4, 0.25)  
X, Y = np.meshgrid(X, Y)  
R = np.sqrt(X**2 + Y**2)  
Z = f(X, Y) 
  
ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=plt.cm.RdBu)  
ax.contourf(X, Y, Z, zdir='z', offset=-3, cmap=plt.cm.RdBu)  
ax.set_zlim(-3,3)  
  
# savefig('../figures/plot3d_ex.png',dpi=48)  
plt.show()