title: Eager Execution - InternalError: Could not find valid device for node name: "Sqrt"
body: <p>With Eager Execution enabled the TensorFlow square-root function <code>tf.sqrt()</code> results in an <code>InternalError</code>.</p>
  
  <pre><code>import tensorflow as tf
  
  # enable eager execution
  tf.enable_eager_execution()
  
  &gt; tf.pow(2,4)
  'Out': &lt;tf.Tensor: id=48, shape=(), dtype=int32, numpy=16&gt;
  
  &gt; tf.sqrt(4)
  
  &gt;&gt;&gt; Traceback (most recent call last):
  
    File "&lt;ipython-input-21-5dc8e2f4780c&gt;", line 1, in &lt;module&gt;
      tf.sqrt(4)
  
    File "/Users/ekababisong/anaconda3/envs/py36_dl/lib/python3.6/site-packages/
       tensorflow/python/ops/math_ops.py", line 365, in sqrt
           return gen_math_ops.sqrt(x, name=name)
  
    File "/Users/ekababisong/anaconda3/envs/py36_dl/lib/python3.6/site-packages/
       tensorflow/python/ops/gen_math_ops.py", line 7795, in sqrt
          _six.raise_from(_core._status_to_exception(e.code, message), None)
  
    File "&lt;string&gt;", line 3, in raise_from
  
  InternalError: Could not find valid device for node name: "Sqrt"
  op: "Sqrt"
  input: "dummy_input"
  attr {
    key: "T"
    value {
      type: DT_INT32
    }
  }
   [Op:Sqrt] name: Sqrt/
  </code></pre>