why returning style loss + style loss?

[songer1993]

I am wondering why style loss + style loss is returned in function closure(). Could you give an explanation?

[alexis-jacq]

wow that's a typo! thanks.. correct is to return content_loss+style_loss, I fixed it.
but interestingly it works anyway...

[songer1993]

Probably because each loss already gets back-propagated when doing 'style_score += sl.backward()' and 'content_score += cl.backward()'.