on"><i class="bi"></i></button></pre></div>
<p>Recall that in Stan, <code>permutation[1:N_train]</code> is an array of integers, so that <code>x[permutation[1 : N_train]]</code> is a vector defined for <code>i in 1:N_train</code> by</p>
<div class="sourceCode" id="cb5"><pre class="sourceCode stan code-with-copy"><code class="sourceCode stan"><span id="cb5-1"><a href="#cb5-1" aria-hidden="true" tabindex="-1"></a>x[permutation[<span class="dv">1</span> : N_train]][i] = x[permutation[<span class="dv">1</span>: