Detection training zero-mAP fix (#192)

ultralytics/yolo/engine/exporter.py

@@ -168,7 +168,7 @@ class Exporter:
 
         # Input
         im = torch.zeros(self.args.batch, 3, *self.imgsz).to(self.device)
-        file = Path(getattr(model, 'pt_path', None) or model.yaml['yaml_file'])
+        file = Path(getattr(model, 'pt_path', None) or getattr(model, 'yaml_file', None) or model.yaml['yaml_file'])
         if file.suffix == '.yaml':
             file = Path(file.name)
 

ultralytics/yolo/engine/model.py

@@ -218,3 +218,4 @@ class YOLO:
         args.pop("batch", None)
         args.pop("epochs", None)
         args.pop("cache", None)
+        args.pop("save_json", None)