MATLAB: Efficient Row x Collumn multiplication

Question

Hi all,

Consider the vectors: A of size; s x 4 B of size; 4 x s

Now, I am only interested in the product A(i,:)*B(:,i) of size s x 1

for i=1,..,s. I.e. only the row times the collumn with the same index.

The solution I found myself is: diag(A*B);

But I think there must be a faster solution, since I calculate many useless matrix elements if s>>4.

Do you guys have a suggestion?

Answer 1

sum(A'.*B)