arithm = base 2, normalisation = w.r.t #symbols (<code class="docutils literal notranslate"><span class="pre">m-1</span></code>)
Note: using the standard PermEn estimation, <code class="docutils literal notranslate"><span class="pre">Perm</span> <span class="pre">=</span> <span class="pre">0</span></code> when <code class="docutils literal notranslate"><span class="pre">m</span> <span class="pre">=</span>
<span class="pre">1</span></code>. It is recommeneded that signal length, N &gt; 5m! 
(see [8] and Amig