Hi Jeremy and everyone, Thank you for good course.
from source code of FastAI
def freeze_to(self, n:int)->None:
"Freeze layers up to layer group `n`."
for g in self.layer_groups[:n]:
for l in g:
if not self.train_bn or not isinstance(l, bn_types): requires_grad(l, False)
for g in self.layer_groups[n:]: requires_grad(g, True)
self.create_opt(defaults.lr)
All batchnorm_layers are unfreeze during finetune. Could you explain why?
and What is self.train_bn? Thank you