A demonstration of NumPy's broadcasting semantics.

broadcasting.py

import numpy as np

a = np.array([[1, 1, 1],
              [2, 2, 2],
              [3, 3, 3]])

b = np.array([1, 2, 3])
c = np.array([[1],
              [2],
              [3]])

print(np.array_equal(a + b,
                     np.array([[2, 3, 4],
                               [3, 4, 5],
                               [4, 5, 6]]))  # True
    
print(np.array_equal(a + c,
                     np.array([[2, 2, 2],
                               [4, 4, 4],
                               [6, 6, 6]]))  # True