title: `estimator.train` with num_steps in Tensorflow
body: <p>I have made a <strong>custom estimator</strong> in <strong>Tensorflow 1.4</strong>. In <code>estimator.train</code>function, I see a <code>steps</code> parameter, which I am using as a way to <strong>stop</strong> the training and then <strong>evaluate</strong> on my <strong>validation dataset</strong>.</p>
  
  
  
  <pre class="lang-python prettyprint-override"><code>while True:
      model.train(input_fn= lambda:train_input_fn(train_data), steps = FLAGS.num_steps)
      model.evaluate(input_fn= lambda:train_input_fn(test_data))
  </code></pre>
  
  <p>After every <code>num_steps</code>, I run evaluate on <strong>validation dataset</strong>. 
  What I am observing is, after <code>num_steps</code>, once the evaluation is done, there is a jerk in the plot of <strong>AUC/Loss functions(in general all metric)</strong>. </p>
  
  <p><strong>Plot attached</strong> : <a href="https://i.stack.imgur.com/2Z2pm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2Z2pm.png" alt="enter image description here"></a></p>
  
  <p>I am unable to understand why it's happening. </p>
  
  <p><strong>Is it not the right way to evaluate <code>metrics</code> on <code>validation dataset</code> at regular intervals</strong>  </p>
  
  <p><a href="https://github.com/adakum/TF_Classification/blob/master/train_tf_II.py#L226-L229" rel="nofollow noreferrer">Link to code</a></p>