   ncol <span class="op">=</span> <span class="va">simmr_tdf</span><span class="op">$</span><span class="va">n_sources</span>,</span></span>
<span class="r-in"><span>    nrow <span class="op">=</span> <span class="va">simmr_tdf</span><span class="op">$</span><span class="va">n_obs</span>,</span></span>
<span class="r-in"><span>    byrow <span class="op">=</span> <span class="cn">TRUE</span></span></span>
<span class="r-in"><span>  <span class="op">)</span></span></span>
<span class="r-in"><span><span class=