Update main.py (pytorch#65)

Author: Junonia

imagenet/main.py

@@ -263,7 +263,7 @@ def update(self, val, n=1):
 def adjust_learning_rate(optimizer, epoch):
  """Sets the learning rate to the initial LR decayed by 10 every 30 epochs"""
  lr = args.lr * (0.1 ** (epoch // 30))
- for param_group in optimizer.state_dict()['param_groups']:
+ for param_group in optimizer.param_groups:
  param_group['lr'] = lr