I have obtained the means and sigmas of 3d Gaussian distribution, then I want to plot the 3d distribution with python code, and obtain the distribution figure.
2 Answers
This is based on documentation of mpl_toolkits and an answer on SO based on scipy multinormal pdf:
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
import numpy as np
from scipy.stats import multivariate_normal
x, y = np.mgrid[-1.0:1.0:30j, -1.0:1.0:30j]
# Need an (N, 2) array of (x, y) pairs.
xy = np.column_stack([x.flat, y.flat])
mu = np.array([0.0, 0.0])
sigma = np.array([.5, .5])
covariance = np.diag(sigma**2)
z = multivariate_normal.pdf(xy, mean=mu, cov=covariance)
# Reshape back to a (30, 30) grid.
z = z.reshape(x.shape)
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
ax.plot_surface(x,y,z)
#ax.plot_wireframe(x,y,z)
plt.show()
reference:-
1 Comment
JTB
Not to be pedantic, but doesn't "3D Gaussian Distribution" imply that the input is 3D? This and the other SO question you linked treat 2D gaussian distributions...
Another example without using scipi:
import numpy as np
import matplotlib.pyplot as plt
ax = plt.axes(projection="3d")
mesh_size=100
max=mesh_size**2
xyz = np.zeros((3,max))
nx, ny = (mesh_size,mesh_size)
x = np.linspace(-1, 1, nx)
y = np.linspace(-1, 1, ny)
xv, yv = np.meshgrid(x, y)
xyz[0]=xv.reshape(max,)
xyz[1]=yv.reshape(max,)
xyz[2]=np.exp(-(xyz[0]**2+xyz[1]**2))
ax.scatter(xyz[0],xyz[1],xyz[2])
ax.set_title("3D Plot")
plt.show()