output.txt

Initial:
[[0 1 1 0 1]
 [0 0 1 0 1]
 [0 0 0 0 0]
 [0 1 1 0 1]
 [0 0 0 0 0]]

Top:
[[0 1 1 0 1]
 [0 0 1 0 1]
 [0 0 0 0 0]
 [0 0 0 0 1]
 [0 0 0 0 0]]

Bottom:
[[0 0 0 0 0]
 [1 0 0 0 0]
 [1 1 0 0 0]
 [0 0 0 0 0]
 [1 1 1 1 0]]

Combined:
[[0 1 1 0 1]
 [1 0 1 0 1]
 [1 1 0 0 0]
 [0 0 0 0 1]
 [1 1 1 1 0]]

test.py

import numpy as np

assignment = np.array([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [1, 0, 0, 0], [0, 0, 0, 1]])
node_ancestry = np.array([[0, 1, 1, 1], [0, 0, 1, 1], [0, 0, 0, 0], [0, 0, 0, 0]])

print('Initial:')
adm_top = np.dot(np.dot(assignment, node_ancestry), assignment.T)
print(adm_top)
print
adm_top = np.triu(adm_top)

node_ancestry = np.logical_not(node_ancestry)
np.fill_diagonal(node_ancestry, 0)
adm_bottom = np.dot(np.dot(assignment, node_ancestry), assignment.T)
adm_bottom = np.tril(adm_bottom)

adm = adm_top + adm_bottom
print('Top:')
print(adm_top)
print
print('Bottom:')
print(adm_bottom)
print
print('Combined:')
print(adm)