Add `inputs_embeds` functionality when generating with BioGPT (#21889)

* initial commit to add inputs_embeds to generation

* formatting

src/transformers/models/biogpt/modeling_biogpt.py

@@ -703,17 +703,27 @@ class BioGptForCausalLM(BioGptPreTrainedModel):
             cross_attentions=outputs.cross_attentions,
         )
 
-    def prepare_inputs_for_generation(self, input_ids, attention_mask, past_key_values=None, **kwargs):
+    def prepare_inputs_for_generation(
+        self, input_ids, attention_mask, inputs_embeds=None, past_key_values=None, **kwargs
+    ):
         # only last token for inputs_ids if past is defined in kwargs
         if past_key_values:
             input_ids = input_ids[:, -1].unsqueeze(-1)
 
-        return {
-            "input_ids": input_ids,
-            "attention_mask": attention_mask,
-            "past_key_values": past_key_values,
-            "use_cache": kwargs.get("use_cache"),
-        }
+        if inputs_embeds is not None and past_key_values is None:
+            model_inputs = {"inputs_embeds": inputs_embeds}
+        else:
+            model_inputs = {"input_ids": input_ids}
+
+        model_inputs.update(
+            {
+                "attention_mask": attention_mask,
+                "past_key_values": past_key_values,
+                "use_cache": kwargs.get("use_cache"),
+            }
+        )
+
+        return model_inputs
 
     @staticmethod
     def _reorder_cache(past_key_values, beam_idx):