</a></span><span class="op">(</span><span class="va">dat</span><span class="op">)</span></span>
<span><span class="va">Q</span> <span class="op">&lt;-</span> <span class="fu"><a href="https://rdrr.io/r/base/matrix.html" class="external-link">matrix</a></span><span class="op">(</span><span class="fl">0</span>,<span class="va">I</span>,<span class="fl">2</span><span class="op">)</span></span>
<span><span class="va">Q</span><span class="op">[</span><span class="fl">1</span><span class="op">:</span><span class=