Propagation function

What am I doing wrong here?

{moderator edit - solution code removed}

Welcome to the course!

BTW we’re not supposed to post our solution code here on the forums (or in any other public place), but I realize it does make it easier to debug. I will go ahead and edit your post to remove the code.

You are using to multiply two row vectors of dimension 1 x m. That will just throw an error because the “inner” dimensions don’t match. Here’s a thread which discusses how dot products work in this regard.

Here’s another thread with a more general discussion of how to choose between elementwise and dot product style multiplications. That thread is also linked from the FAQ Thread which is worth a look if you are just getting started here.