How to calculate the outer product of two matrices A and B per rows faster in python (numpy)?

Question

Let say we have two matrices A and B.

A has the shape (r, k) and B has the shape (r, l).

Now I want to calculate the np.outer product of these two matrices p

Answer 1

You could literally transfer the iterators as string notation to np.einsum -

np.einsum('rk,rl->kl',A,B)

Or with matrix-multiplication using np.dot -

A.T.dot(B)