Update metrics names (#85)

ultralytics/yolo/v8/detect/train.py

@@ -46,6 +46,7 @@ class DetectionTrainer(BaseTrainer):
         return model
 
     def get_validator(self):
+        self.loss_names = 'box_loss', 'obj_loss', 'cls_loss'
         return v8.detect.DetectionValidator(self.test_loader,
                                             save_dir=self.save_dir,
                                             logger=self.console,
@@ -190,15 +191,14 @@ class DetectionTrainer(BaseTrainer):
         loss = lbox + lobj + lcls
         return loss * bs, torch.cat((lbox, lobj, lcls)).detach()
 
-    # TODO: improve from API users perspective
     def label_loss_items(self, loss_items=None, prefix="train"):
         # We should just use named tensors here in future
-        keys = [f"{prefix}/lbox", f"{prefix}/lobj", f"{prefix}/lcls"]
+        keys = [f"{prefix}/{x}" for x in self.loss_names]
         return dict(zip(keys, loss_items)) if loss_items is not None else keys
 
     def progress_string(self):
         return ('\n' + '%11s' * 6) % \
-               ('Epoch', 'GPU_mem', 'box_loss', 'obj_loss', 'cls_loss', 'Size')
+               ('Epoch', 'GPU_mem', *self.loss_names, 'Size')
 
     def plot_training_samples(self, batch, ni):
         images = batch["img"]