ass="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>:N_train][i]]</span>
<span id="cb5-2"><a href="#cb5-2" aria-hidden="true" tabindex="-1"></a>                               = x[permutation[i]]</span></code><button title="Copy to Clipboard" class="code-copy-button"><i class="bi"></i></button></pre></div>
<p>Given the test/train