Scale rows of 3D-tensor

Question

I have an n-by-3-by-3 numpy array A and an n-by-3 numpy array B. I\'d now like to

Answer 1

You can use NumPy broadcasting to let the elementwise multiplication happen in a vectorized manner after extending B to 3D after adding a singleton dimension at the end with np.newaxis or its alias/shorthand None. Thus, the implementation would be A*B[:,:,None] or simply A*B[...,None].