hi, i have a question, in lecture notes of the third week of course, why T(transpose sign) is not placed above of W matrix?

Hi, @Pouya_Hosseinniya. Although I am not sure what you’re looking at, the accepted mathematical notation uses a `T`

or prime (\prime) superscripted on the matrix that is to be transposed: X^T or X^\prime, for example. In this course, the `T`

-notation is used.

If you are referring to the computational analogue in Python/NumPy, then we have `X.T`

.

Because Prof Ng has defined the layout of the W matrix so that a transpose is no longer required. It is required in the Logistic Regression case only because he chooses to define the weight vector w as a column vector. Here’s another recent post that talks about this in more detail.

thanks

my question is that in the picture that i uploaded the W

^{[1]}.T has not used and only W

^{[2]}has been written here. why?

thank you for your help.