Evolution commented `hyp['anchors']` fix (#3887)

Fix for `KeyError: 'anchors'` error when start hyperparameter evolution: ```bash python train.py --evolve ``` ```bash Traceback (most recent call last): File "E:\yolov5\train.py", line 623, in <module> hyp[k] = max(hyp[k], v[1]) # lower limit KeyError: 'anchors' ```

Evolution commented `hyp['anchors']` fix (#3887)
8930e22c · Glenn Jocher · GitHub · 3c3f8fbd · 8930e22c
--- a/train.py
+++ b/train.py
@@ -596,6 +596,8 @@ def main(opt):

        with open(opt.hyp) as f:
            hyp = yaml.safe_load(f)  # load hyps dict
+            if 'anchors' not in hyp:  # anchors commented in hyp.yaml
+                hyp['anchors'] = 3
        assert LOCAL_RANK == -1, 'DDP mode not implemented for --evolve'
        opt.notest, opt.nosave = True, True  # only test/save final epoch
        # ei = [isinstance(x, (int, float)) for x in hyp.values()]  # evolvable indices