title: How to get PI in tensorflow?
body: <p>I could not find any information about mathemtical constants in the Tensorflow API</p>
  
  <p>neither in <a href="https://www.tensorflow.org/versions/r0.12/api_docs/python/math_ops/basic_math_functions" rel="noreferrer">Basic Math functions</a> nor in <a href="https://www.tensorflow.org/api_guides/python/math_ops" rel="noreferrer">Math Ops</a>.</p>
  
  <p>I was able to get it by</p>
  
  <pre><code>import math as m
  pi = tf.constant(m.pi)
  </code></pre>
  
  <p>However, this would mean to include another library, - so I wonder if there is this functionallity for mathemtical  constants like <code>pi</code>, or <code>euler</code> already provided inside tensorflow? </p>