title: different distance depending on input order using fastdtw in python
body: <p>I want to find similarities between time-series and perform Dynamic Time Warping in python using fastdtw (<a href="https://github.com/slaypni/fastdtw/tree/master/fastdtw" rel="nofollow noreferrer">https://github.com/slaypni/fastdtw/tree/master/fastdtw</a>).
  The computed distance is sometimes changing according to the input order, especially for long time-series.
  Here is an example:</p>
  
  <pre><code>x = np.random.rand(44)
  y = np.random.rand(40)
  d1, inx1 = fastdtw(y, x)
  d2, inx2= fastdtw(y, x)
  d1, d2
  </code></pre>
  
  <p>Any idea why?</p>