fix incomplete progress bar when refresh_rate > num batches

[awaelchli]

What does this PR do?

Fixes #4565

Fixes edge cases with num batches not being divisibale by refresh rate, leading to an incomplete the progress bar.
Tests here fail on master.

Example:

train_batches: 5, refresh_rate: 3

(master)
Epoch 0: 60%|██████ | 3/5 [00:00<00:00, 111.11it/s, loss=0.131]

(this branch)
Epoch 0: 100%|██████████| 5/5 [00:00<00:00, 125.00it/s, loss=0.124]

[awaelchli]

this bugfix is a visual fix, I need to figure out how to write the unit test. somehow counting the number of times update is called.

[SkafteNicki]

@awaelchli would it be idea for testing to subclass ProgressBar and then decorate the update method? Something like:

class MyProgressBar(ProgressBar):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._update_counter = 0

    def init_train_tqdm(self):
        bar = super().init_train_tqdm()
        bar.update = self.counter_wrap(bar.update)
        return bar

    def counter_wrap(self, update):
        def wrap(*args, **kwargs):
            self._update_counter += 1
            return update(*args, **kwargs)
        return wrap

[codecov]

Codecov Report

Merging #4577 (00a24b4) into master (9186abe) will increase coverage by 0%.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master   #4577    +/-   ##
=======================================
  Coverage      93%     93%            
=======================================
  Files         118     118            
  Lines        8911    9030   +119     
=======================================
+ Hits         8285    8403   +118     
- Misses        626     627     +1     

[SkafteNicki]

LGTM

[ananyahjha93]

@awaelchli can you resolve the conflict?

[awaelchli]

@ananyahjha93 resolved, thanks!