Integrate `total_batch_idx` with progress tracking (#8598)

CHANGELOG.md

@@ -12,6 +12,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Added `state_id` property to the `Callback` base class ([#6886](https://github.com/PyTorchLightning/pytorch-lightning/pull/6886))
 
 
+- Progress tracking
+    * Integrate `TrainingEpochLoop.total_batch_idx` ([#8598](https://github.com/PyTorchLightning/pytorch-lightning/pull/8598)
+
+
 - Added `batch_size` and `rank_zero_only` arguments for `log_dict` to match `log` ([#8628](https://github.com/PyTorchLightning/pytorch-lightning/pull/8628))
 
 

pytorch_lightning/loops/epoch/training_epoch_loop.py

@@ -39,8 +39,7 @@ class TrainingEpochLoop(loops.Loop):
         self.min_steps: int = min_steps
         self.max_steps: int = max_steps
         self.global_step: int = 0
-        # the total batch index across all epochs
-        self.total_batch_idx: int = 0
+        # manually tracking which is the last batch is necessary for iterable dataset support
         self.is_last_batch: Optional[bool] = None
         self.batch_progress = Progress()
         self.scheduler_progress = SchedulerProgress()
@@ -53,6 +52,13 @@ class TrainingEpochLoop(loops.Loop):
         self._warning_cache: WarningCache = WarningCache()
         self._epoch_output: Optional[List[List[STEP_OUTPUT]]] = None
 
+    @property
+    def total_batch_idx(self) -> int:
+        """Returns the current batch index (across epochs)"""
+        # use `ready` instead of `completed` in case this is accessed after `completed` has been increased
+        # but before the next `ready` increase
+        return self.batch_progress.total.ready - 1
+
     @property
     def batch_idx(self) -> int:
         """Returns the current batch index (within this epoch)"""
@@ -176,14 +182,9 @@ class TrainingEpochLoop(loops.Loop):
         # update plateau LR scheduler after metrics are logged
         self.update_lr_schedulers("step", update_plateau_schedulers=True)
 
-        self.total_batch_idx += 1
-
         # progress global step according to grads progress
         self._increment_accumulated_grad_global_step()
 
-        if self.done:
-            raise StopIteration
-
     def on_run_end(self) -> List[List[STEP_OUTPUT]]:
         """Calls the on_epoch_end hook.
 
@@ -351,7 +352,7 @@ class TrainingEpochLoop(loops.Loop):
         """Increments global step according to grads progress"""
         if not self._should_accumulate():
             self.global_step = self.trainer.accelerator.update_global_step(
-                self.total_batch_idx, self.trainer.global_step
+                self.batch_progress.current.ready, self.trainer.global_step
             )
 
     def _should_check_val_fx(self, batch_idx: int, is_last_batch: bool) -> bool:

pytorch_lightning/loops/fit_loop.py

@@ -63,12 +63,12 @@ class FitLoop(Loop):
 
     @property
     def total_batch_idx(self) -> int:
-        """Returns the total number of batches already run (across all epochs)"""
+        """Returns the current batch index (across epochs)"""
         return self.epoch_loop.total_batch_idx
 
     @property
     def batch_idx(self) -> int:
-        """Returns the number of batches already run within this epoch"""
+        """Returns the current batch index (within this epoch)"""
         return self.epoch_loop.batch_idx
 
     @property

tests/tuner/test_lr_finder.py

@@ -184,7 +184,7 @@ def test_accumulation_and_early_stopping(tmpdir):
 
     assert lrfinder.suggestion() != 1e-3
     assert len(lrfinder.results["lr"]) == 100
-    assert lrfinder._total_batch_idx == 200
+    assert lrfinder._total_batch_idx == 199
 
 
 def test_suggestion_parameters_work(tmpdir):