p><em>Moving deviations</em></p>
<pre><code class="language-txt">x mdev y     mdev[x;y]
</code></pre>
<p>Where</p>
<ul>
    <li><code>x</code> is a positive int atom</li>
    <li><code>y</code> is a numeric list</li>
</ul>
<p>returns the floating-point <code>x</code>-item moving deviations of <code>y</code>, with any nulls after the first
    item replaced by zero. The first <code>x</code> items of the result are the deviations of the terms so far, and
    thereafter the result is the moving deviation.</p>
<pre><code class="language-q">q)2 mdev 1 2 3 5 7 10
0 0.5 0.5 1 1 1.5
q)5 mdev 1 2 3 5 7 10
0 0.5 0.8164966 1.47902 2.154066 2.87054
q)5 mdev 0N 2 0N 5 7 0N    / nulls after the first are replaced by 0
0n 0 0 1.5 2.054805 2.054805

q)t
b c
----
1 45
2 46
3 47
q)2 mdev t
b   c
-------
0   0
0.5 0.5
0.5 0.5
</code></pre>
<p><code>mdev</code> is a uniform function.</p>