Bugfix to implement floor division (I replaced / with //)
Author: lorenzobalzani
Pull request: yes

# What does this PR do?

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Error encountered:
RuntimeError: Integer division of tensors using div or / is no longer supported, and in a future release div will perform true division as in Python 3. Use true_divide or floor_divide (// in Python) instead.

I just replaced / with //.

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Comments:
Didn't we recently change all `//` to ` ... / ).long()` @nreimers ?

Hi @lorenzobalzani 

It was changed in: #13573 

Starting with PyTorch 1.9, // creates a warning and might be removed in future PyTorch versions.

Which Pytorch version are you using that leads to this error? 

This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/master/CONTRIBUTING.md) are likely to be ignored.

Hi, I'm getting this error as well when running a summarization pipeline task

@Weilin37 what are your version numbers of Python, Pytorch and transformers? 

> @Weilin37 what are your version numbers of Python, Pytorch and transformers?

Nevermind on this. I upgraded all my versions and it was fixed.

@Weilin37 Could you still tell what your previous versions were? So that I can have a look at which constellation this happens.

> @Weilin37 Could you still tell what your previous versions were? So that I can have a look at which constellation this happens.

I had transformers 4.9.0
torch 1.6.0
Python 3.8

I upgraded both transformers and torch to the latest version (as well as other packages that it depends on) and it seemed to work fine.

This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/master/CONTRIBUTING.md) are likely to be ignored.