update the code of examples/pytorch/metapath2vec.py (#2463)

Co-authored-by: Quan (Andy) Gan <coin2028@hotmail.com>

examples/pytorch/metapath2vec/metapath2vec.py

@@ -36,11 +36,11 @@ class Metapath2VecTrainer:
 
     def train(self):
 
-        for iteration in range(self.iterations):
-            print("\n\n\nIteration: " + str(iteration + 1))
         optimizer = optim.SparseAdam(self.skip_gram_model.parameters(), lr=self.initial_lr)
         scheduler = torch.optim.lr_scheduler.CosineAnnealingLR(optimizer, len(self.dataloader))
 
+        for iteration in range(self.iterations):
+            print("\n\n\nIteration: " + str(iteration + 1))
             running_loss = 0.0
             for i, sample_batched in enumerate(tqdm(self.dataloader)):