YOLOv5 v5.0 Release patch 1 (#2764)

* torch.jit.trace(model, img, strict=False)

* Update check_file()

* Update hubconf.py

* Update README.md

README.md

 Model |size<br><sup>(pixels) |mAP<sup>val<br>0.5:0.95 |mAP<sup>test<br>0.5:0.95 |mAP<sup>val<br>0.5 |Speed<br><sup>V100 (ms) | |params<br><sup>(M) |FLOPS<br><sup>640 (B)
 ---   |---  |---        |---         |---             |---                |---|---              |---
 [YOLOv5s][assets]    |640  |36.7     |36.7     |55.4     |**2.0** | |7.3   |17.0
-[YOLOv5m][assets]    |640  |44.5     |44.5     |63.3     |2.7     | |21.4  |51.3
+[YOLOv5m][assets]    |640  |44.5     |44.5     |63.1     |2.7     | |21.4  |51.3
 [YOLOv5l][assets]    |640  |48.2     |48.2     |66.9     |3.8     | |47.0  |115.4
 [YOLOv5x][assets]    |640  |**50.4** |**50.4** |**68.8** |6.1     | |87.7  |218.8
 | | | | | | || |

hubconf.py

-"""File for accessing YOLOv5 models via PyTorch Hub https://pytorch.org/hub/ultralytics_yolov5/
+"""YOLOv5 PyTorch Hub models https://pytorch.org/hub/ultralytics_yolov5/
 
 Usage:
     import torch
     Returns:
         pytorch model
     """
-    config = Path(__file__).parent / 'models' / f'{name}.yaml'  # model.yaml path
     try:
-        model = Model(config, channels, classes)
+        cfg = list((Path(__file__).parent / 'models').rglob(f'{name}.yaml'))[0]  # model.yaml path
+        model = Model(cfg, channels, classes)
         if pretrained:
             fname = f'{name}.pt'  # checkpoint filename
             attempt_download(fname)  # download if not found locally

models/export.py

     try:
         print('\nStarting TorchScript export with torch %s...' % torch.__version__)
         f = opt.weights.replace('.pt', '.torchscript.pt')  # filename
-        ts = torch.jit.trace(model, img)
+        ts = torch.jit.trace(model, img, strict=False)
         ts.save(f)
         print('TorchScript export success, saved as %s' % f)
     except Exception as e:

utils/general.py

 
 def check_file(file):
     # Search for file if not found
-    if os.path.isfile(file) or file == '':
+    if Path(file).is_file() or file == '':
         return file
     else:
         files = glob.glob('./**/' + file, recursive=True)  # find file
-        assert len(files), 'File Not Found: %s' % file  # assert file was found
-        assert len(files) == 1, "Multiple files match '%s', specify exact path: %s" % (file, files)  # assert unique
+        assert len(files), f'File Not Found: {file}'  # assert file was found
+        assert len(files) == 1, f"Multiple files match '{file}', specify exact path: {files}"  # assert unique
         return files[0]  # return file