Hi Gregor,
I'm afraid in the first exercise notebook there is a slight mix-up with the dimensions of the matrices and vectors involved. In the introductory text of 1.2.2 it says and
. However, if the input vector is
and the output vector is
, as specified in the code blocks, and following
, then the weight matrix has the dimension
and the bias vector is
. The same applies to the text in 1.2.4, where
and
have been swapped.
Please let me know if I am wrong.
Best regards,
Lasse