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NumPy Matrix Multiplication

Let’s learn how to perform matrix multiplication in NumPy. We can use the matmul() function, dot() function, or @ operator tp perform the multiplication.

NumPy Matrix Multiplication

For multiplying two matrices using the dot product:

AxB

If the dimension of A is MxN, then the dimension of B must be NxP, resulting in a matrix of MxP.

Using matmul() function

z = np.matmul(x, y)

Using the dot() function

z = np.dot(x, y)

Using @ operator

We can also use the @ operator to perform the matrix multiplication as shown:

z = x @ y

Example

The code shows matrix multiplication on two matrices.

# NumPy Matrix Multiplication
# NumPy Tutorials – www.TestingDocs.com

import numpy as np

x = np.array([[1,5,3], [2,6,9]])

y = np.array([[3,8,2,9],[2,19,2,7],
[1,35,2,8]])

# NumPy Matrix Multiplication
z= np.matmul(x, y)

print(“—————“)
print(“x:”,x)
print(“—————“)
print(“y:”,y)
print(“—————“)
print(“z:”,z)
print(“—————“)
print(x.shape, y.shape, z.shape)

NumPy Matrix Multiplication