title: tqdm not showing bar
body: <p>I'm using the tqdm library and it doesn't give me the progress bar, instead it gives me output that looks like this where it just tells me the iteration:</p>
  
  <p><code>251it [01:44,  2.39it/s]</code></p>
  
  <p>Any idea why the code would do this? I thought it was maybe because I was passing it a generator but then again I've used generators in the past that have worked. I've never really messed with tdqm formatting before. Here is part of the source code:</p>
  
  <pre><code>train_iter = zip(train_x, train_y) #train_x and train_y are just lists of elements
  ....
  def train(train_iter, model, criterion, optimizer):
      model.train()
      total_loss = 0
      for x, y in tqdm(train_iter):
          x = x.transpose(0, 1)
          y = y.transpose(0, 1)
          optimizer.zero_grad()
          bloss = model.forward(x, y, criterion)   
          bloss.backward()
          torch.nn.utils.clip_grad_norm(model.parameters(), args.clip)
          optimizer.step()        
          total_loss += bloss.data[0]
      return total_loss
  </code></pre>