Fix anchor incorrectly initialized (#8891)

* Fix anchor incorrectly initialized

Using --noautoanchor and --evolve simultaneously leads to anchor incorrectly initialized. --noautoanchor denotes anchors don't need to evolve, thus removing anchors from hyp will fix it.

* Update train.py

* Update train.py

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

train.py

@@ -569,6 +569,8 @@ def main(opt, callbacks=Callbacks()):
             hyp = yaml.safe_load(f)  # load hyps dict
             if 'anchors' not in hyp:  # anchors commented in hyp.yaml
                 hyp['anchors'] = 3
+        if opt.noautoanchor:
+            del hyp['anchors'], meta['anchors']
         opt.noval, opt.nosave, save_dir = True, True, Path(opt.save_dir)  # only val/save final epoch
         # ei = [isinstance(x, (int, float)) for x in hyp.values()]  # evolvable indices
         evolve_yaml, evolve_csv = save_dir / 'hyp_evolve.yaml', save_dir / 'evolve.csv'