Need check_val_every_n_steps in Trainer
🚀 Feature
Add an argument check_val_every_n_steps in Trainer.__init__ function to check metrics of validation set for certain steps.
Motivation
For many tasks, large models are trained in steps not complete epochs, especially pretrained models in CV and NLP. As a consequence, step-based arguments like max_steps, log_every_n_steps may be more convenient than epoch-based ones. However, the Trainer API only has a check_val_every_n_epoch argument for computing metrics of validation data. It's very helpful to have an additional argument like check_val_every_n_steps in Trainer constructor.
Pitch
Trainer.init(..., check_val_every_n_epoch=1, check_val_every_n_steps=100, ...)