The first two columns are the indices of the clusters</span>
0027 <span class="comment">%     that were aggregated; the index assigned to the aggregate for future</span>
0028 <span class="comment">%     entries is the lower of the two original indices.  The third column is</span>
0029 <span class="comment">%     the connection strength between the clusters before aggregation and the</span>
0030 <span class="comment">%     fourth column is the isi statistic for the aggregate (0 if isi statistics</span>
0031 