Early exit on predict entrypoint if epoch has completed (#972)

Summary: Pull Request resolved: #972

Reviewed By: galrotem, anshulverma

Differential Revision: D69865409

fbshipit-source-id: 814dd7081ed7489c63eb021c1bd1ff3abaeb47c7

Author: diego-urgell

tests/framework/test_predict.py

@@ -21,6 +21,7 @@
 from torchtnt.framework.predict import predict
 from torchtnt.framework.state import State
 from torchtnt.framework.unit import PredictUnit, TPredictUnit
+from torchtnt.utils.progress import Progress
 from torchtnt.utils.timer import Timer
 
 
@@ -242,6 +243,16 @@ def test_predict_ckpt_autograd_mode(
                 predict(unit, dataloader, callbacks=cast(List[Callback], callbacks))
                 mock_autograd_mode.assert_called_once()
 
+    def test_predict_epoch_check(self) -> None:
+        unit = MagicMock(wraps=DummyPredictUnit(2))
+        unit.predict_progress = Progress(num_epochs_completed=1, num_steps_completed=5)
+
+        dataloader = generate_random_dataloader(10, 2, 2)
+
+        predict(unit, dataloader, max_steps_per_epoch=100)
+
+        unit.on_predict_start.assert_not_called()
+
 
 Batch = Tuple[torch.Tensor, torch.Tensor]
 

torchtnt/framework/predict.py

@@ -122,6 +122,12 @@ def _predict_impl(
     # input validation
     predict_state = none_throws(state.predict_state)
 
+    if predict_unit.predict_progress.num_epochs_completed >= 1:
+        logger.warning(
+            "Predict epoch has already been completed. Skipping to avoid duplicate outputs."
+        )
+        return
+
     state._active_phase = ActivePhase.PREDICT
     logger.info(
         f"Started predict with max_steps_per_epoch={predict_state.max_steps_per_epoch}"