Unified model loading with backwards compatibility (#132)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

ultralytics/yolo/engine/exporter.py

@@ -164,8 +164,8 @@ class Exporter:
             assert not self.args.dynamic, '--half not compatible with --dynamic, i.e. use either --half or --dynamic'
 
         # Checks
-        if self.args.batch_size == 16:
-            self.args.batch_size = 1  # TODO: resolve batch_size 16 default in config.yaml
+        # if self.args.batch_size == model.args['batch_size']:  # user has not modified training batch_size
+        self.args.batch_size = 1
         self.imgsz = check_imgsz(self.args.imgsz, stride=model.stride, min_dim=2)  # check image size
         if self.args.optimize:
             assert self.device.type == 'cpu', '--optimize not compatible with cuda devices, i.e. use --device cpu'
@@ -778,7 +778,7 @@ def export(cfg):
         if Path(cfg.model).suffix == '.yaml':
             model = DetectionModel(cfg.model)
         elif Path(cfg.model).suffix == '.pt':
-            model = attempt_load_weights(cfg.model)
+            model = attempt_load_weights(cfg.model, fuse=True)
         else:
             TypeError(f'Unsupported model type {cfg.model}')
     exporter(model=model)

ultralytics/yolo/engine/model.py

@@ -77,13 +77,12 @@ class YOLO:
         Args:
             weights (str): model checkpoint to be loaded
         """
-        self.ckpt = torch.load(weights, map_location="cpu")
-        self.task = self.ckpt["train_args"]["task"]
-        self.overrides = dict(self.ckpt["train_args"])
+        self.model = attempt_load_weights(weights)
+        self.task = self.model.args["task"]
+        self.overrides = self.model.args
         self.overrides["device"] = ''  # reset device
         self.ModelClass, self.TrainerClass, self.ValidatorClass, self.PredictorClass = \
             self._guess_ops_from_task(self.task)
-        self.model = attempt_load_weights(weights, fuse=False)
 
     def reset(self):
         """
@@ -189,7 +188,7 @@ class YOLO:
             raise AttributeError("dataset not provided! Please define `data` in config.yaml or pass as an argument.")
 
         self.trainer = self.TrainerClass(overrides=overrides)
-        self.trainer.model = self.trainer.load_model(weights=self.ckpt,
+        self.trainer.model = self.trainer.load_model(weights=self.model,
                                                      model_cfg=self.model.yaml if self.task != "classify" else None)
         self.model = self.trainer.model  # override here to save memory
 

ultralytics/yolo/engine/validator.py

@@ -106,6 +106,9 @@ class BaseValidator:
                 data = check_dataset_yaml(self.args.data)
             else:
                 data = check_dataset(self.args.data)
+
+            if self.device.type == 'cpu':
+                self.args.workers = 0  # faster CPU val as time dominated by inference, not dataloading
             self.dataloader = self.dataloader or \
                               self.get_dataloader(data.get("val") or data.set("test"), self.args.batch_size)