Matrix multiplication
Published in
2 min readJan 10, 2019
Refer to this video by mathispower4u
Practice:
A fairly simple way to remember how to do matrix multiplication:
Assume that two matrices multiply together as AB = C.
You need to write out each entries of the product, and then place this entry with a row of A and a column of B which numbered as subscriptions of this entry.
e.g., in the Product Matrix, C₁₁ represents Row-1 of A multiplies Column-1 of B;
C₂₁ represents Row-2 of A multiplies Column-1 of B.
So on and so forth, write down all the entries of the product entries, and then use dot product to calculate each one.
Properties of matrix multiplication
Refer to Khan academy article.
Einstein summation convention
Refer to Wiki: Einstein notation
