2
$\begingroup$

I found a loss function of a perceptron on a book is in this form

$$ L(w,b) = - \sum\limits_{x_i \in M}y_i(wx_i+b) $$

In the context of machine learning loss functions, is it acceptable to put $x_i$ on the bottom of a summation notation?

$\endgroup$
4
$\begingroup$

It just means to sum over all $x_i$ in $M$. That is completely acceptable notation.

| improve this answer | |
$\endgroup$
  • $\begingroup$ Adding to what @Dave pointed out, when optimizing a perceptron you are essentially compute the loss for each input in your training dataset and sum that. To do that you need to traverse the full training data set, which is exactly what $\sum_{x_i \in M}$ means. $\endgroup$ – thushv89 Jun 12 '19 at 4:36

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.