【python-plt】二元正态密度函数图像，,import num

【python-plt】二元正态密度函数图像，,import num

import numpy as npimport matplotlib.pyplot as pltfrom matplotlib import cmfrom matplotlib.ticker import LinearLocator, FormatStrFormatterx=np.arange(-10,10,0.5)y=xX,Y=np.meshgrid(x,y)def norm_d(x1,x2,mu1,mu2,s1,s2,rho):    num=((1)/(2*np.pi*s1*s2*np.sqrt(1-rho**2)))    A=((x1-mu1)**2)/(s1**2)    B=2*rho*(((x1-mu1)*(x2-mu2))/(s1*s2))    C=((x2-mu2)**2)/(s2**2)    D=-1/(2*(1-rho**2))*(A-B+C)    pdf=num*np.exp(D)    return 2dnmR=norm_d(X,Y,0,0,1,3,0.75)fig = plt.figure()ax = fig.gca(projection='3d')surf = ax.plot_surface(X, Y, R, cmap=cm.coolwarm,linewidth=0, antialiased=False)plt.show()

\(\sigma_1^2=1,\sigma_2^2=3,\rho=0.75\)

\(\sigma_1^2=1,\sigma_2^2=1,\rho=0\)

【python-plt】二元正态密度函数图像