用Python随机设定初始位置

Question

I am now working to make rotational trajectories. In the beginning I need to define the initial position of an rotating object. How to make 1000 random initial position in three dimensions of this kind of object by Python or NumPy? I think a python function can solve the problem.

Answer 1

If I understand the question, you need to pick up point uniformly distributed on a sphere. See here for details.

import math
import numpy as np

cos_theta = 2.0 * np.random.random(100) - 1.0
phi       = 2.0 * math.pi * np.random.random(100)

sin_theta = np.sqrt( (1.0 - cos_theta)*(1.0 + cos_theta) )

x = sin_theta * np.cos(phi)
y = sin_theta * np.sin(phi)
z = cos_theta

print(x, y, z)
print("---------------------")
print(np.square(x) + np.square(y) + np.square(z))