fix bugs (#793)

Author: Jintao-Huang

swift/llm/infer.py

@@ -257,7 +257,7 @@ def llm_infer(args: InferArguments) -> None:
     if args.save_result:
         result_dir = args.ckpt_dir
         if result_dir is None:
-            result_dir = model.model_dir
+            result_dir = llm_engine.model_dir if args.infer_backend == 'vllm' else model.model_dir
         if result_dir is not None:
             result_dir = os.path.join(result_dir, 'infer_result')
             os.makedirs(result_dir, exist_ok=True)