ue will be added to the  aggregation. For very large datasets, this is a bit faster than using filter before  the aggregation.</li>
</ul>
<p>Example:</p>
<pre><code class="java">//Begin parallelized expansion
Iterable dsSeq = (Iterable)rowMapcat(srcds, tallyDays, hashmap(kw(&quot;result-type&quot;), kw(&quot;as-seq&quot;)));

//The first aggregation is to summarize by placement and simulation the year-month tallies.
//We are essentially replacing count with a summarized count.  After this statement
//we can