</span><span class="va">dense_comm</span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="va">sparse_comm</span></span></span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 6 x 4 sparse Matrix of class "dgCMatrix"</span>
<span class="r-out co"><span class="r-pr">#&gt;</span>    sp1 sp2 sp3 sp4</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> g1   1   1   1   .</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> g2   .   .   1   .</span>
<span clas