allow non-packing pretraining

Former-commit-id: 3fee5cc5a3db9ce874ad90f2500ec092d904bd4e

src/llmtuner/train/dpo/trainer.py

@@ -22,7 +22,7 @@ class CustomDPOTrainer(DPOTrainer):
         ftx_gamma: float,
         model: Union["PreTrainedModel", torch.nn.Module],
         ref_model: Optional[Union["PreTrainedModel", torch.nn.Module]] = None,
-        disable_dropout: Optional[bool] = True,
+        disable_dropout: bool = True,
         **kwargs,
     ):
         if disable_dropout:
@@ -95,7 +95,7 @@ class CustomDPOTrainer(DPOTrainer):
         self,
         model: "PreTrainedModel",
         batch: Dict[str, torch.Tensor],
-        train_eval: Optional[Literal["train", "eval"]] = "train",
+        train_eval: Literal["train", "eval"] = "train",
     ) -> Tuple[torch.Tensor, Dict[str, torch.Tensor]]:
         r"""
         Computes the DPO loss and other metrics for the given batch of inputs for train or test.