[Sirupsen]

Great questions, I struggled with this part the most when I was learning it.

`.grad` is set by `autograd` when calling `backward()`

Probably the easiest way to understand this is to play a bit with `.grad` and `backward()` on their own, with the first code sample in the `autograd` section [1].

[1]: https://sirupsen.com/napkin/neural-net#automagically-computi...

[gbersac]

Thank you!