Fix shape error that occurred when loading lora weight of gemma2 mode…

…l. (#2330)

python/sglang/srt/models/gemma2.py

@@ -355,6 +355,40 @@ def forward(
             input_ids, hidden_states, self.model.embed_tokens, forward_batch
         )
 
+    def get_hidden_dim(self, module_name):
+        # return input_dim, output_dim
+        if module_name in ["q_proj", "qkv_proj"]:
+            return (
+                self.config.hidden_size,
+                self.config.head_dim * self.config.num_attention_heads,
+            )
+        elif module_name in ["o_proj"]:
+            return (
+                self.config.head_dim * self.config.num_attention_heads,
+                self.config.hidden_size,
+            )
+        elif module_name in ["kv_proj"]:
+            return (
+                self.config.hidden_size,
+                self.config.head_dim * self.config.num_key_value_heads,
+            )
+        elif module_name == "gate_up_proj":
+            return self.config.hidden_size, self.config.intermediate_size
+        elif module_name == "down_proj":
+            return self.config.intermediate_size, self.config.hidden_size
+        else:
+            raise NotImplementedError()
+
+    def get_module_name(self, name):
+        params_mapping = {
+            "q_proj": "qkv_proj",
+            "k_proj": "qkv_proj",
+            "v_proj": "qkv_proj",
+            "gate_proj": "gate_up_proj",
+            "up_proj": "gate_up_proj",
+        }
+        return params_mapping.get(name, name)
+
     def get_attention_sliding_window_size(self):
         return get_attention_sliding_window_size(self.config)