fixed warning of changed torch behaviour

order in which optimizer and lr_scheduler have to be called switched
see: https://pytorch.org/docs/stable/optim.html#how-to-adjust-learning-rate

Deep-SAD-PyTorch/src/optim/DeepSAD_trainer.py

@@ -83,13 +83,6 @@ class DeepSADTrainer(BaseTrainer):
         net.train()
         for epoch in range(self.n_epochs):
 
-            scheduler.step()
-            if epoch in self.lr_milestones:
-                logger.info(
-                    "  LR scheduler: new learning rate is %g"
-                    % float(scheduler.get_lr()[0])
-                )
-
             epoch_loss = 0.0
             n_batches = 0
             epoch_start_time = time.time()
@@ -117,6 +110,13 @@ class DeepSADTrainer(BaseTrainer):
                 epoch_loss += loss.item()
                 n_batches += 1
 
+            scheduler.step()
+            if epoch in self.lr_milestones:
+                logger.info(
+                    "  LR scheduler: new learning rate is %g"
+                    % float(scheduler.get_lr()[0])
+                )
+
             # log epoch statistics
             epoch_train_time = time.time() - epoch_start_time
             logger.info(