title: What does np.sqrt (2.0 / 9/64) mean?
body: <p>There was the following tensor flow code</p>
  
  <pre><code>conv_w = tf.get_variable ("conv_% 02d_w"% (i + 1), [9,9,64,64], initializer = tf.random_normal_initializer (stddev=np.sqrt(2.0/9/64)))
  </code></pre>
  
  <p>I do not know what "(2.0 / 9/64)" in "np.sqrt" means here.</p>
  
  <p>Why is the division operator (/) twice?</p>
  
  <p>That code is probably a normal distribution.</p>
  
  <p>I wonder what 2.0, 9, and 64 each do.</p>