title: Save Tensorflow graph for viewing in Tensorboard without summary operations
body: <p>I have a rather complicated Tensorflow graph that I'd like to visualize for optimization purposes. Is there a function that I can call that will simply save the graph for viewing in Tensorboard without needing to annotate variables?</p>
  
  <p>I Tried this:</p>
  
  <pre><code>merged = tf.merge_all_summaries()
  writer = tf.train.SummaryWriter("/Users/Name/Desktop/tf_logs", session.graph_def)
  </code></pre>
  
  <p>But no output was produced. This is using the 0.6 wheel.</p>
  
  <p>This appears to be related:
  <a href="https://stackoverflow.com/questions/33773271/graph-visualisaton-is-not-showing-in-tensorboard-for-seq2seq-model">Graph visualisaton is not showing in tensorboard for seq2seq model</a></p>