[v1] Support multimodal Ulysses CP and memory-efficient chunk loss for SFT (#10762)

src/llamafactory/v1/trainers/dpo_trainer.py

@@ -96,6 +96,8 @@ class DPOTrainer(BaseTrainer):
     ) -> None:
         if args.cp_size > 1:
             raise NotImplementedError("DPO trainer currently only supports cp_size == 1.")
+        if args.chunk_loss_size is not None:
+            raise NotImplementedError("Chunk Loss currently only supports SFT training.")
 
         self.pref_loss = args.pref_loss
         self.pref_beta = args.pref_beta