Testing the effect of Sybil columns on eigenvectors

gistfile1.py

import numpy as np
from numpy import linalg as LA
M = np.random.random((3,3))

# Normalize columns
M_norms = np.apply_along_axis(LA.norm, 0, M)
M = M / M_norms

# Create a sybil column
# append rows of zeros (nobody in original M votes for it)
M2 = np.append(M, [[0,0,0]], 0)
# append sybil column
Vsybil = np.random.random((4,1))
Vsybil /= LA.norm(Vsybil)
M2 = np.append(M2, Vsybil, 1)

w, v = LA.eig(M)
w2, v2 = LA.eig(M2)

# Compare eigenvectors before and after sybil
v
v2