add conditional statement for auxiliary loss calculation (#23899)

* add conditional statement for auxiliary loss calculation

* fix style and copies

src/transformers/models/beit/modeling_beit.py

@@ -1192,8 +1192,10 @@ class BeitForSemanticSegmentation(BeitPreTrainedModel):
         # compute weighted loss
         loss_fct = CrossEntropyLoss(ignore_index=self.config.semantic_loss_ignore_index)
         main_loss = loss_fct(upsampled_logits, labels)
+        loss = main_loss
+        if auxiliary_logits is not None:
             auxiliary_loss = loss_fct(upsampled_auxiliary_logits, labels)
-        loss = main_loss + self.config.auxiliary_loss_weight * auxiliary_loss
+            loss += self.config.auxiliary_loss_weight * auxiliary_loss
 
         return loss
 

src/transformers/models/data2vec/modeling_data2vec_vision.py

@@ -1120,8 +1120,10 @@ class Data2VecVisionForSemanticSegmentation(Data2VecVisionPreTrainedModel):
         # compute weighted loss
         loss_fct = CrossEntropyLoss(ignore_index=self.config.semantic_loss_ignore_index)
         main_loss = loss_fct(upsampled_logits, labels)
+        loss = main_loss
+        if auxiliary_logits is not None:
             auxiliary_loss = loss_fct(upsampled_auxiliary_logits, labels)
-        loss = main_loss + self.config.auxiliary_loss_weight * auxiliary_loss
+            loss += self.config.auxiliary_loss_weight * auxiliary_loss
 
         return loss