+ default model on llmchatgens init

topos/generations/chat_gens.py

@@ -4,12 +4,27 @@
 
 # Assuming OpenAI is a pre-defined client for API interactions
 
+default_models = {
+    "groq": "llama-3.1-70b-versatile",
+    "openai": "gpt-4o",
+    "ollama": "dolphin-llama3"
+    }
+
 class LLMChatGens:
     def __init__(self, model_name: str, provider: str, api_key: str):
         self.provier = provider
         self.api_key = api_key
         self.client = LLMClient(provider, api_key).get_client()
-        self.model_name = model_name
+        self.model_name = self._init_model(model_name, provider)
+
+    def _init_model(self, model_name: str, provider: str):
+        if len(model_name) > 0:
+            return model_name
+        else:
+            if provider == 'ollama':
+                return model_name
+            else:
+                return default_models[provider]
 
     def stream_chat(self, message_history: List[Dict[str, str]], temperature: float = 0) -> Generator[str, None, None]:
         try: