title: restore Tensorflow model without extracting from directory
body: <p>I'm currently saving and restoring neural network models using Tensorflow's <a href="https://www.tensorflow.org/api_docs/python/tf/train/Saver" rel="noreferrer"><code>Saver</code></a> class, as shown below:</p>
  
  <p><code>saver.save(sess, checkpoint_prefix, global_step=step)</code></p>
  
  <p><code>saver.restore(sess, checkpoint_file)</code></p>
  
  <p>This saves <code>.ckpt</code> files of the model to a specified path. Because I am running multiple experiments, I have limited space to save these models. </p>
  
  <p>I would like to know if there is a way to save these models without saving content in specified directories.</p>
  
  <p>Ex. can I just pass some object at the last checkpoint to some evaluate() function and restore the model from that object? </p>
  
  <p>So far as I see, the <code>save_path</code> parameter in <code>tf.train.Saver.restore()</code> is not optional.</p>
  
  <p>Any insight would be much appreciated.</p>
  
  <p>Thanks</p>