title: Creating a tensorflow Variable without setting the initial value
body: <p>I'm learning Tensorflow these days.</p>
  
  <p>When we create a Tensor using tf.Variable, the first argument is "initial_value". So, even if we don't have specific values as initial values in mind, this value must be given.</p>
  
  <p>The following is an example:</p>
  
  <pre><code>a = tf.Variable(tf.zeros([784, 200]), name="a")
  </code></pre>
  
  <p>I think in some cases, we do not want to set the initial values, since the variable will be evaluated later as shown below:</p>
  
  <pre><code>a = c + e  # where "c" and "e" are some Tensor variables.
  </code></pre>
  
  <p>My question is in the above case, initializing the above <code>a</code> using <code>tf.zeros([784, 200])</code> is completely waste of computation. What would be the best practice in such cases?</p>