Update train.py (#3667)

train.py

@@ -22,7 +22,7 @@ from torch.nn.parallel import DistributedDataParallel as DDP
 from torch.utils.tensorboard import SummaryWriter
 from tqdm import tqdm
 
-import test  # import test.py to get mAP after each epoch
+import test  # for end-of-epoch mAP
 from models.experimental import attempt_load
 from models.yolo import Model
 from utils.autoanchor import check_anchors
@@ -39,7 +39,11 @@ from utils.wandb_logging.wandb_utils import WandbLogger, check_wandb_resume
 logger = logging.getLogger(__name__)
 
 
-def train(hyp, opt, device, tb_writer=None):
+def train(hyp,
+          opt,
+          device,
+          tb_writer=None
+          ):
     logger.info(colorstr('hyperparameters: ') + ', '.join(f'{k}={v}' for k, v in hyp.items()))
     save_dir, epochs, batch_size, total_batch_size, weights, rank, single_cls = \
         Path(opt.save_dir), opt.epochs, opt.batch_size, opt.total_batch_size, opt.weights, opt.global_rank, \
@@ -341,7 +345,7 @@ def train(hyp, opt, device, tb_writer=None):
                                                   save_dir.glob('train*.jpg') if x.exists()]})
 
             # end batch ------------------------------------------------------------------------------------------------
-        
+
         # Scheduler
         lr = [x['lr'] for x in optimizer.param_groups]  # for tensorboard
         scheduler.step()
@@ -404,12 +408,11 @@ def train(hyp, opt, device, tb_writer=None):
                     torch.save(ckpt, best)
                 if wandb_logger.wandb:
                     if ((epoch + 1) % opt.save_period == 0 and not final_epoch) and opt.save_period != -1:
-                        wandb_logger.log_model(
-                            last.parent, opt, epoch, fi, best_model=best_fitness == fi)
+                        wandb_logger.log_model(last.parent, opt, epoch, fi, best_model=best_fitness == fi)
                 del ckpt
 
         # end epoch ----------------------------------------------------------------------------------------------------
-    # end training
+    # end training -----------------------------------------------------------------------------------------------------
     if rank in [-1, 0]:
         logger.info(f'{epoch - start_epoch + 1} epochs completed in {(time.time() - t0) / 3600:.3f} hours.\n')
         if plots: