Update default value for nb_epochs in AdversarialTrainerMadryPGD

- to match 80'000 training steps of Madry et al.

Signed-off-by: Beat Buesser <[email protected]>

Author: Beat Buesser

art/defences/trainer/adversarial_trainer_madry_pgd.py

@@ -54,7 +54,7 @@ class AdversarialTrainerMadryPGD(Trainer):
     def __init__(
         self,
         classifier: "CLASSIFIER_LOSS_GRADIENTS_TYPE",
-        nb_epochs: Optional[int] = 391,
+        nb_epochs: Optional[int] = 205,
         batch_size: Optional[int] = 128,
         eps: Union[int, float] = 8,
         eps_step: Union[int, float] = 2,