Fix number of total steps shown in progress bar during sanity validation check when number of validation dataloaders >= 2 (#597)

* type: debug Calculate the adequate number of steps to run during sanity_check. This fixes the bug when there are two or more validation dataloaders. - Before: total=self.num_sanity_val_steps - After: total=self.num_sanity_val_steps*len(self.get_val_dataloaders()) * type: refactor Put total=... in the next line * type: refactor run flake8

Author: YehCF

pytorch_lightning/trainer/trainer.py

@@ -491,7 +491,8 @@ def run_pretrain_routine(self, model):
  ref_model.on_sanity_check_start()
  if self.get_val_dataloaders() is not None and self.num_sanity_val_steps > 0:
  # init progress bars for validation sanity check
- pbar = tqdm.tqdm(desc='Validation sanity check', total=self.num_sanity_val_steps,
+ pbar = tqdm.tqdm(desc='Validation sanity check',
+ total=self.num_sanity_val_steps * len(self.get_val_dataloaders()),
  leave=False, position=2 * self.process_position,
  disable=not self.show_progress_bar, dynamic_ncols=True, unit='batch')
  self.main_progress_bar = pbar