IterableDataset breaks 1.1 compatibility

[volcacius]

A recently introduced feature unfortunately breaks compability with Pytorch 1.1.0.

Describe the bug
IterableDataset support, introduced in issue 323, requires Pytorch 1.2.0+.

To Reproduce
In a python environment with Pytorch 1.1.0 do:
import pytorch_lightning

Expected behavior
Compatibility with Pytorch 1.1.0. I'm filing it as a bug report rather than a docs fix since the dependency on 1.2.0+ introduced by issue 323 doesn't seem to be intentional.

[williamFalcon]

good catch. mind submitting a PR? was not the intention of that fix :)

We want to support 1.1

[Borda]

I have played with versions and it seems to me that it does not run even with 1.2.0; see #462

[williamFalcon]

weird. let’s patch it and make a nee release? in the meantime, put a note on the readme to use 0.5.2.1 if you need pt 1.1 or 1.2 support?

[Borda]

you may rather change requirements.txt and after fix put it back...
I see that >=1.2.0 is there already for some time... 8-)

[shreyasbapat]

Is this already fixed? I see that torch 1.2.0 is already in requirements.txt ?

[Borda]

I think not yet...8-)

[shreyasbapat]

Do you suggest torch 1.3.0 ?

[williamFalcon]

we need to support 1.2.0 :)

[williamFalcon]

@Borda did we get this fixed? is PT 1.2 supported now? If not, what do we need to do?

[Borda]

I have not worked on it yet (bit busy with docs), hopefully this week...