SSIM update does not work for the last batch (if batch size is different)

[vinayak015]

🐛 Bug description

Environment

• PyTorch Version :1.10.1
• Ignite Version ():0.4.8
• OS : Ubuntu
• How you installed Ignite (conda, pip, source):
• Python version: 3.9
• Any other relevant information:

If the previous batch and the current batch are different then it throws the error. Attaching the screen shot of error.

Screenshot of the basic code is also attached.

[vfdev-5]

Thanks for reporting @vinayak015 ! Looks like a bug.

cc @ydcjeff

[vinayak015]

Thank you for accepting the bug report. I am happy to work on it, if that's alright.

[sdesrozis]

@vinayak015 Thank you for your help !

[vfdev-5]

@vinayak015 yes, thanks for proposing to help.
Let me expose here how I would tackle the issue.

1. Create a test that would reproduce the issue and fail with the current codebase
2. Fix the implementation of SSIM

Please, take a look of our contributing guide for info : https://github.com/pytorch/ignite/blob/master/CONTRIBUTING.md

[vinayak015]

I will work on it after 11th April, as I do not have bandwidth left right now. In the mean time the temporary workaround is to drop the last batch!

[vfdev-5]

@vinayak015 any chance you could work on this issue ?

[vinayak015]

Hey @vfdev-5, I am on holiday for the next 15 days. (It was a sudden plan). Please feel free to unassign me if its priority has been increased.