How to use EarlyStopping and ModelCheckpoint
The logs passed into the on_epoch_end method of both ModelCheckpoint and EarlyStopping seems to have the loss field set to a string, which leads to exception when comparing with the last best result. Following codes in trainer.py,
 407     @property
 408     def __training_tqdm_dict(self):
 409         tqdm_dict = {
 410             'loss': '{0:.3f}'.format(self.avg_loss),
 411             'epoch': '{}'.format(self.current_epoch),
 412             'batch_nb': '{}'.format(self.batch_nb),
 413         }

How should I use the ModelCheckpoint and EarlyStopping, is adding my own field in progress field when returning from training_step the way to go? What is the purpose of converting to string?
What's your environment?

conda version (no venv)   4.7.12
PyTorch version   1.2.0
Lightning version   0.5.0
Test-tube version  0.7.1