Filling zero after `optimizer.step()`

[ray1007]

Once the bug in pytorch is fixed, I'll remove this line.

The bug is described in pytorch forum and reported in github.

[ssnl]

FYI, it is fixed today. But it is only fixed on master.

[ray1007]

Thanks! I'll fix this after a pip version is released. :)

Tzu-Ray

[luffycodes]

hello, i was wondering if the issue is fixed ?

thank you for the code :)