Pass epoch outputs to callback hooks `on_validation_epoch_end` and `on_test_epoch_end`

[rsaite]

🚀 Feature

The callback hook on_validation_epoch_end(self, trainer, pl_module) should receive the outputs of the validation epoch, changing its signature to on_validation_epoch_end(self, trainer, pl_module, outputs), same for the hook on_test_epoch_end. This functionality has already been implemented for on_train_epoch_end.

Motivation

I have different models where I want to do the same things with the validation/test outputs after each epoch: write predictions out to a dataframe and create plots based on the outputs. Separating this functionality from my modules by using a callback (instead of polluting all my modules with this code) seems to be the proper way.

This feature request is related to the open issues #4689 and #4369 concerning a bug in on_train_epoch_end.

[github-actions]

Hi! thanks for your contribution!, great first issue!

[hackgoofer]

#4369 fixes it!

[rsaite]

No, it does not. #4369 fixes an existing bug in the hook on_train_epoch_end s.t. it correctly receives the training outputs.

This issue requests that the validation and test outputs should be passed to the respective hooks on_validation_epoch_end and on_test_epoch_end. This is currently not implemented and is not resolved by #4369.

[stale]

This issue has been automatically marked as stale because it hasn't had any recent activity. This issue will be closed in 7 days if no further activity occurs. Thank you for your contributions, Pytorch Lightning Team!

[kaushikb11]

@Borda @tchaton Is there a reason why we don't pass epoch outputs to on_validation_epoch_end and on_test_epoch_end? Or something on the roadmap?