add option for resizing embeddings when adding new tokens (#2000)

* add option for resizing embeddings when adding new tokens

* let's just be opinonated about this setting and set it to False

src/axolotl/utils/config/models/input/v0_4_1/__init__.py

@@ -549,6 +549,7 @@ class AxolotlInputConfig(
     resume_from_checkpoint: Optional[str] = None
     auto_resume_from_checkpoints: Optional[bool] = None
     resize_token_embeddings_to_32x: Optional[bool] = None
+    mean_resizing_embeddings: Optional[bool] = False
 
     rl: Optional[RLType] = None
     reward_model: Optional[bool] = None

src/axolotl/utils/models.py

@@ -1042,7 +1042,10 @@ class ModelLoader:
             hasattr(self.model, "get_input_embeddings")
             and self.model.get_input_embeddings().num_embeddings < embeddings_len
         ):
-            self.model.resize_token_embeddings(embeddings_len)
+            resize_kwargs = {}
+            if self.cfg.mean_resizing_embeddings is not None:
+                resize_kwargs["mean_resizing"] = self.cfg.mean_resizing_embeddings
+            self.model.resize_token_embeddings(embeddings_len, **resize_kwargs)
         else:
             self.model.tie_weights()