If f(w) = log(sigmoid(w^T*x)) calculate the gradient (d/dw) of f(w)

Question

w is an (nx1) vector and X is an (nxn) matrix. Here's my work:

However this site (http://www.matrixcalculus.org/) says that the derivative should be

What am I doing wrong?

***Please*** review [ask], as well as look at the [help/on-topic] before asking further questions. — user3483203, Feb 08 '20 at 19:45

score -1 · Accepted Answer · answered Feb 08 '20 at 19:43

-1

The solutions are actually the same, if you take my (the first one) solution and expand it out with a common denominator you will get the second solution.

answered Feb 08 '20 at 19:43

AmmarMZ

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If f(w) = log(sigmoid(w^T*x)) calculate the gradient (d/dw) of f(w)

1 Answers1