title: Compare two elements of the same Numpy array through broadcasting
body: <p>I have a numpy array of 2000 elements and I want to find out the indexes in which the element minus the next element divided by itself is bigger than x.</p>
  <p>Something like:</p>
  <pre><code>a[abs(a[i] - a[i+1])/a[i+1] &gt; x]
  </code></pre>
  <p>I am looking for a way to do this by broadcasting instead of a for loop.</p>