#Vectorization:
#
#To speed up computation, avoid loops as much as possible. Instead,
#use matrix/vector addition multiplication, where possible

#Here, assume v, v1, v2 are numpy arrays

#Slower:
s = 0
for elem in v:
    s += elem**2
    
#Faster:
sum(v**2)

#or:
dot(v.T, v)

#or:
from numpy.linalg import norm
norm(v)**2

#Slower:
s = 0
for i in range(len(v1)):
    s += (v1[i]-v2[i])**2
    
#Faster:
sum((v1-v2)**2)
#or.....