Unload models on request (#471 from Brawlence/main)

server.py

@@ -50,12 +50,17 @@ def get_available_softprompts():
 def get_available_loras():
     return ['None'] + sorted([item.name for item in list(Path('loras/').glob('*')) if not item.name.endswith(('.txt', '-np', '.pt', '.json'))], key=str.lower)
 
+def unload_model():
+    shared.model = shared.tokenizer = None
+    clear_torch_cache()
+
 def load_model_wrapper(selected_model):
     if selected_model != shared.model_name:
         shared.model_name = selected_model
-        shared.model = shared.tokenizer = None
-        clear_torch_cache()
-        shared.model, shared.tokenizer = load_model(shared.model_name)
+
+        unload_model()
+        if selected_model != '':
+            shared.model, shared.tokenizer = load_model(shared.model_name)
 
     return selected_model