[tune/raysgd] Tune API for TorchTrainer + Fix State Restoration (#7547)

python/ray/util/sgd/torch/training_operator.py

@@ -168,8 +168,10 @@ class TrainingOperator:
 
             if self.use_tqdm and self.world_rank == 0:
                 _progress_bar.n = batch_idx + 1
+                postfix = {}
                 if "train_loss" in metrics:
-                    _progress_bar.set_postfix({"loss": metrics["train_loss"]})
+                    postfix.update(loss=metrics["train_loss"])
+                _progress_bar.set_postfix(postfix)
 
             if self.scheduler and batch_info.get(
                     SCHEDULER_STEP) == SCHEDULER_STEP_BATCH:
@@ -259,7 +261,7 @@ class TrainingOperator:
 
         Returns:
             A dict of metrics from the evaluation.
-                By default, returns "mean_accuracy" and "mean_val_loss"
+                By default, returns "val_accuracy" and "val_loss"
                 which is computed by aggregating "loss" and "correct" values
                 from ``validate_batch`` and dividing it by the sum of
                 ``num_samples`` from all calls to ``self.validate_batch``.