Python求两向量夹角

import numpy as np

a1 = np.array([1, 1, 4, 4, 1, 1, 4, 4, 1/4, 1/4, 1, 1, 1/4, 1/4, 1, 1])
a2 = np.array([1, 2, 1, 4, 1/2, 1, 1/2, 1/3, 1, 2, 1, 4, 1/4, 3, 1/4, 1])
a3 = np.array([1, 2, 4, 3, 1/2, 1, 3, 2, 1/4, 1/3, 1, 1/2, 1/3, 1/2, 2, 1])
a4 = np.array([1, 3, 1, 3, 1/3, 1, 1/3, 1, 1, 3, 1, 3, 1/3, 1, 1/3, 1])

def get_pq(a1, a2):
La1 = np.sqrt(a1.dot(a1))
La2 = np.sqrt(a2.dot(a2))
cos_ang = a1.dot(a2) / (La1*La2)
return cos_ang
# print(cos_ang)

c1 = get_pq(a4, a1)
c2 = get_pq(a4, a2)
c3 = get_pq(a4, a3)

print(c1 + c2 + c3)