fix ChatGLM lm_head #494

Former-commit-id: bf0048abdaeb2b9592d38ac991704ad014370b47

src/llmtuner/tuner/core/loader.py

@@ -153,6 +153,10 @@ def load_model_and_tokenizer(
     if "GenerationMixin" not in str(model.generate.__func__):
         model.generate = MethodType(PreTrainedModel.generate, model)
 
+    # Fix LM head (for ChatGLM2)
+    if not hasattr(model, "lm_head"):
+        setattr(model, "lm_head", model.transformer.output_layer)
+
     # Register auto class to save the custom code files.
     if isinstance(config, PretrainedConfig) and "AutoConfig" in getattr(config, "auto_map", {}):
         config.__class__.register_for_auto_class()

src/llmtuner/tuner/dpo/trainer.py

@@ -32,11 +32,11 @@ class DPOPeftTrainer(PeftModelMixin, DPOTrainer):
         self._stored_metrics = defaultdict(lambda: defaultdict(list))
 
         Trainer.__init__(self, **kwargs)
+        if not hasattr(self, "accelerator"):
+            raise AttributeError("Please update `transformers`.")
+
         if ref_model is not None:
-            if hasattr(self, "accelerator"):
-                self.ref_model = self.accelerator.prepare_model(self.ref_model, evaluation_mode=True)
-            else:
-                raise AttributeError("Please update `transformers`.")
+            self.ref_model = self.accelerator.prepare_model(self.ref_model, evaluation_mode=True)
 
     def concatenated_forward(
         self,