Merge branch 'dev_1.5.2' into development_issue_837

Author: beat-buesser

art/attacks/evasion/shadow_attack.py

@@ -174,12 +174,12 @@ def _get_regularisation_loss_gradients(self, perturbation: np.ndarray) -> np.nda
         :param perturbation: The perturbation to be regularised.
         :return: The loss gradients of the perturbation.
         """
+        if not self.estimator.channels_first:
+            perturbation = perturbation.transpose((0, 3, 1, 2))
+
         if self.framework == "tensorflow":
             import tensorflow as tf
 
-            if not self.estimator.channels_first:
-                perturbation = perturbation.transpose((0, 3, 1, 2))
-
             if tf.executing_eagerly():
                 with tf.GradientTape() as tape:
 
@@ -205,9 +205,6 @@ def _get_regularisation_loss_gradients(self, perturbation: np.ndarray) -> np.nda
                     loss = self.lambda_tv * loss_tv + self.lambda_s * loss_s + self.lambda_c * loss_c
                     gradients = tape.gradient(loss, perturbation_t).numpy()
 
-                    if not self.estimator.channels_first:
-                        gradients = gradients.transpose(0, 2, 3, 1)
-
             else:
                 raise ValueError("Expecting eager execution.")
 
@@ -238,6 +235,9 @@ def _get_regularisation_loss_gradients(self, perturbation: np.ndarray) -> np.nda
         else:
             raise NotImplementedError
 
+        if not self.estimator.channels_first:
+            gradients = gradients.transpose(0, 2, 3, 1)
+
         return gradients
 
     def _check_params(self) -> None: