set the default value of progress_bar_refresh_rate to 1 (#1100)

pytorch_lightning/trainer/__init__.py

@@ -619,13 +619,13 @@ Example::
 progress_bar_refresh_rate
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 How often to refresh progress bar (in steps).
-Faster refresh rates (lower number), in notebooks is known to crash them
-because of their screen refresh rates. 50 is optimal for those cases.
+In notebooks, faster refresh rates (lower number) is known to crash them
+because of their screen refresh rates, so raise it to 50 or more.
 
 Example::
 
     # default used by the Trainer
-    trainer = Trainer(progress_bar_refresh_rate=50)
+    trainer = Trainer(progress_bar_refresh_rate=1)
 
 
 reload_dataloaders_every_epoch

pytorch_lightning/trainer/trainer.py

@@ -88,7 +88,7 @@ class Trainer(
             num_tpu_cores: Optional[int] = None,
             log_gpu_memory: Optional[str] = None,
             show_progress_bar: bool = True,
-            progress_bar_refresh_rate: int = 50,
+            progress_bar_refresh_rate: int = 1,
             overfit_pct: float = 0.0,
             track_grad_norm: int = -1,
             check_val_every_n_epoch: int = 1,