title: Assertion error when comparing two float tensors
body: <p>I'm using tensorflow-10.0 with gpu support, and I want to compare if 2 equations return the the same thing (which they actually should). I simplified the second equation up to the point where both equations are equal, but the assert returns that they are not.</p>
  
  <p>In the following code snippet b,c,d are float32 tensors and calculated above.</p>
  
  <pre><code>a1 = tf.reduce_sum(-1/2 - 1/2*b + 1/2*tf.exp(c) + 1/2*tf.square(d), 1)
  a2 = tf.reduce_sum(-1/2 - 1/2*b + 1/2*tf.exp(c) + 1/2*tf.square(d), 1)
  
  a1 = control_flow_ops.with_dependencies([tf.assert_equal(a1, a2)], a1)
  </code></pre>
  
  <blockquote>
    <p>tensorflow.python.framework.errors.InvalidArgumentError: assertion
    failed: [Condition x == y did not hold element-wise: x = ] [../Sum:0]
    [0.038984224 0.047407709 0.043144785...] [y = ] [../Sum_1:0]
    [0.038984239 0.047407985 0.043144524...]</p>
  </blockquote>
  
  <p>Is there a reason, why comparing two float32 vectors lead to an assertion error (even the equation is deterministic, and handling the same values)? Rounding errors should be occur for both equations the same way, or am I wrong?</p>
  
  <p>Thanks in advance!</p>