n> The Partial sum Function</h3>
<p>The partial sum function must have the following signature where the type <code>T</code>, and the types of all the shared arguments (<code>T1</code>, <code>T2</code>, …) match those of the original <code>reduce_sum</code> (<code>reduce_sum_static</code>) call.</p>
<pre><code>(T[] x_subset, int start, int end, T1 s1, T2 s2, ...):real</code></pre>
<p>The partial sum function returns the sum of the <code>start</code> to <code>end</code> terms (inclusive) of the overall cal