matrix multiplication program in python code example

Example 1: matrix multiplication in python

# input two matrices of size n x m 
matrix1 = [[12,7,3], 
        [4 ,5,6], 
        [7 ,8,9]] 
matrix2 = [[5,8,1], 
        [6,7,3], 
        [4,5,9]] 
  
res = [[0 for x in range(3)] for y in range(3)]  
  
# explicit for loops 
for i in range(len(matrix1)): 
    for j in range(len(matrix2[0])): 
        for k in range(len(matrix2)): 
  
            # resulted matrix 
            res[i][j] += matrix1[i][k] * matrix2[k][j] 
  
print (res)

Example 2: python matrix multiplication

>>> a = np.array([[ 5, 1 ,3], 
                  [ 1, 1 ,1], 
                  [ 1, 2 ,1]])
>>> b = np.array([1, 2, 3])
>>> print a.dot(b)
array([16, 6, 8])