-link">round</a></span><span class="op">(</span><span class="va">dt.obs</span> <span class="op">/</span> <span class="va">dt.sim</span><span class="op">)</span><span class="op">)</span></span>
<span><span class="va">t.obs</span> <span class="op">=</span> <span class="va">t.sim</span><span class="op">[</span><span class="va">ids</span><span class="op">]</span></span>
<span><span class="va">y</span> <span class="op">=</span> <span class="va">x</span><span class="op">[</span><span class="va">ids</span><span cl