an class="kw">parameters</span> {</span>
<span id="cb6-2"><a href="#cb6-2" aria-hidden="true" tabindex="-1"></a>  <span class="dt">real</span> alpha;</span>
<span id="cb6-3"><a href="#cb6-3" aria-hidden="true" tabindex="-1"></a>  <span class="dt">real</span> beta;</span>
<span id="cb6-4"><a href="#cb6-4" aria-hidden="true" tabindex="-1"></a>  <span class="dt">real</span>&lt;<span class="kw">lower</span>=<span class="dv">0</span>&gt; sigma;</span>
<span id="cb6-5"><a href="#cb6-5" aria-hidden="true" tabindex