Gradient Field of 3D Gaussian

import matplotlib.pyplot as plt
import numpy as np

# Gradient of Gaussian function
n = 6
x = np.linspace(-2, 2, n)
y = np.linspace(-2, 2, n)
z = np.linspace(-2, 2, n)
X, Y, Z = np.meshgrid(x, y, z)

# Gradient of exp(-(x^2+y^2+z^2))
r2 = X**2 + Y**2 + Z**2
U = -2 * X * np.exp(-r2)
V = -2 * Y * np.exp(-r2)
W = -2 * Z * np.exp(-r2)

fig = plt.figure(figsize=(10, 8), facecolor='#ffffff')
ax = fig.add_subplot(111, projection='3d', facecolor='#ffffff')

ax.quiver(X, Y, Z, U, V, W, length=0.5, normalize=True,
          color='#7c3aed', alpha=0.8, arrow_length_ratio=0.3)

ax.set_xlim(-2.5, 2.5)
ax.set_ylim(-2.5, 2.5)
ax.set_zlim(-2.5, 2.5)

ax.set_xlabel('X', color='#1f2937', fontsize=10)
ax.set_ylabel('Y', color='#1f2937', fontsize=10)
ax.set_zlabel('Z', color='#1f2937', fontsize=10)
ax.set_title('Gradient Field of 3D Gaussian', color='#1f2937', fontsize=14, fontweight='bold', pad=20)

ax.tick_params(colors='#6b7280', labelsize=8)
ax.xaxis.pane.fill = False
ax.yaxis.pane.fill = False
ax.zaxis.pane.fill = False
ax.xaxis.pane.set_edgecolor('#e5e7eb')
ax.yaxis.pane.set_edgecolor('#e5e7eb')
ax.zaxis.pane.set_edgecolor('#e5e7eb')

ax.view_init(elev=25, azim=45)
plt.tight_layout()
plt.show()