title: python RuntimeWarning: invalid value encountered in subtract x = asanyarray(arr - arrmean)
body: <p>I'm just getting the hang of deep learning recently and I wanted to have a go at running <a href="https://github.com/hendriks73/directional_cnns/tree/master/directional_cnns" rel="nofollow noreferrer">this CNN</a> to see how it runs + the output. Because it was only for a test and I don't have a GPU, I used a very small training set (69 files) and validation set (20) and ran it with that with a batch size of 16.</p>
  
  <p>It seems to run just fine. However, I'm getting these errors in each epoch:</p>
  
  <pre><code>  x = asanyarray(arr - arrmean)
  C:\Users\\directional_cnns-master\directional_cnns\normalizer.py:15: RuntimeWarning: invalid value encountered in subtract
    data = data.copy() - mean
  C:\Users\\AppData\Local\Programs\Python\Python36\lib\site-packages\numpy\core\_methods.py:117: RuntimeWarning: invalid value encountered in subtract
    x = asanyarray(arr - arrmean)
  C:\Users\\directional_cnns-master\directional_cnns\normalizer.py:15: RuntimeWarning: invalid value encountered in subtract
    data = data.copy() - mean
  C:\Users\\AppData\Local\Programs\Python\Python36\lib\site-packages\tensorflow\python\keras\callbacks.py:1234: RuntimeWarning: invalid value encountered in less
    if self.monitor_op(current - self.min_delta, self.best):
  </code></pre>
  
  <p>Patience is set too 100 so after every 100th epoch it early stops and restarts. I'm under the impression that this isn't normal, but I'm not sure how to approach this issue. Any help would be appreciated!     </p>