title: Numpy array getting only items and indexes in an ascending order
body: <p>Suppose I have the following array:</p>
  <p><code>arr = [1,2,4,5,6,5,4,3,2,3,4,5,6,7,8]</code></p>
  <p>I want to get only the items which are in ascending order, and ignore the &quot;reverse&quot; in he middle.</p>
  <p>So for this array I want to get:
  <code>res = [1,2,4,5,6,7,8]</code>
  ,at the indexes: <code>[0,1,2,4,13,14]</code></p>
  <p>Any idea?</p>