title: how to initialize Tensor for torch.cat
body: <pre><code>import torch
  
  #Y_pred = ?
  
  for xi in X_iter:
      y_pred = net(xi).argmax(dim=1)
      Y_pred = torch.cat([Y_pred, y_pred])
  </code></pre>
  
  <p>How do you initialize this tensor, or is there a better way to write it？</p>