Check if cuda available

Signed-off-by: junjie.jiang <junjie.jiang@zilliz.com>

clip.py

@@ -96,7 +96,11 @@ class Clip(NNOperator):
     def __init__(self, model_name: str, modality: str, device: str = 'cpu', checkpoint_path: str = None):
         self.model_name = model_name
         self.modality = modality
-        self.device = device
+        if not torch.cuda.is_available():
+            log.warning("Gpu not available, use cpu")
+            self.device = 'cpu'
+        else:
+            self.device = device
         self.checkpoint_path = checkpoint_path
         config = self._configs()
         real_name = model_name