Monitor on training_epoch_end with ModelCheckpoint

[tchaton]

What does this PR do?

Fixes #4797

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[pep8speaks]

Hello @tchaton! Thanks for updating this PR.

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2020-12-14 07:40:07 UTC

[codecov]

Codecov Report

Merging #5084 (985d4f0) into master (b4d926b) will increase coverage by 0%.
The diff coverage is 94%.

@@          Coverage Diff           @@
##           master   #5084   +/-   ##
======================================
  Coverage      93%     93%           
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  Files         134     134           
  Lines        9905    9913    +8     
======================================
+ Hits         9204    9213    +9     
+ Misses        701     700    -1     

[carmocca]

(misclicked approve instead of comment) 🙃

misclick

[rohitgr7]

I disagree with the warning here. checkpoint_callback should monitor the metric logged in training_epoch_end and create checkpoints accordingly whether or not validation_step is happening or not.

[carmocca]

This test is missing a pytest.warns check with the warning thrown 😄

Also it might be better to test

os.listdir(tmpdir) == ['epoch=0.ckpt', ...]

instead of testing that the rest don't exist

[tchaton]

The warning was removed. Also, I am thinking it might be better not to merge this PR as it is a wacky solution and work a on train_sanity check instead. @carmocca @rohitgr7 What are your thoughts?

[rohitgr7]

yes, let's close this one for now.