Adding two matrices using numpy.ndarray with Example

Adding two matrices - Two dimensional ndarray objects:

For adding two matrixes together both the matrices should have equal number of rows and columns.
To add two matrices, the corresponding elements of each matrix are added and placed in the same position in the resultant matrix.
The result of the matrix addition is a matrix of the same number of rows and columns.
The ndarray of NumPy module supports matrix addition through the method __add__() which adds two ndarray objects of the same shape and returns the sum as another ndarray object.

Example:

# import numpy module

import numpy as np

# import python standard library module - random

import random

# Routine for printing a 2x2 matrix

def PrintMatrix(matrix_in):

for x in range(0, matrix_in.shape[0]):

for y in range(0, matrix_in.shape[1]):

print("%d \t"%(matrix_in[x][y]), end='')

if(y%3>1):

print("\n")

# Function to populate a 2x2 matrix with random data

def FillMatrix(matrix_in):

for x in range(0, matrix_in.shape[0]):

for y in range(0, matrix_in.shape[1]):

matrix_in[x][y] = random.randrange(2, 10) + 2

# Create matrices using ndarray

matrix1 = np.ndarray((3,3))

matrix2 = np.ndarray((3,3))

# Fill the matrices i.e., the two dimensional arrays created using ndarray objects

FillMatrix(matrix1)

FillMatrix(matrix2)

# Add two matrices - two nd arrays

add_results = matrix1.__add__(matrix2)

# Print Matrix1

print("Matrix1:")

PrintMatrix(matrix1)

# Print Matrix2

print("Matrix2:")

PrintMatrix(matrix2)

# Print the results of adding two matrices

print("Result of adding Matrix1 and Matrix2:")

PrintMatrix(add_results)

Output:

Matrix1:

8 4 7

7 9 7

11 9 7

Matrix2:

5 7 5

7 11 10

9 11 5

Result of adding Matrix1 and Matrix2:

13 11 12

14 20 17

20 20 12