</span>       <span class="co"># initialize a.init with Q-matrix</span></span>
<span><span class="co"># provide starting values for slopes of first three items on Dimension 1</span></span>
<span><span class="va">a.init</span><span class="op">[</span><span class="fl">1</span><span class="op">:</span><span class="fl">3</span>,<span class="fl">1</span><span class="op">]</span> <span class="op">&lt;-</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="o