Matrix multiplication with another Matrix
We use the dot product to do matrix-matrix multiplication. We will use the same function for this also.
prod = numpy.matmul(a,b) # a and b are matrices
For a matrix-matrix multiplication, there are certain important points:
- The number of columns in the first matrix should be equal to the number of rows in the second matrix.
- If we are multiplying a matrix of dimensions m x n with another matrix of dimensions n x p, then the resultant product will be a matrix of dimensions m x p
We will define two 3 x 3 matrix:
Python3
import numpy as np a = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]]) b = np.array([[11, 22, 33], [44, 55, 66], [77, 88, 99]]) print("Matrix a =", a) print("Matrix b =", b) print("Product of a and b =", np.matmul(a, b)) |
Output:
Parallel matrix-vector multiplication in NumPy
In this article, we will discuss how to do matrix-vector multiplication in NumPy.