While working at Resonai, I wrote a piece of code that performs Hierarchical Clustering, in collaboration with David Lehavi. In addition to various optimizations I won't get into, we applied a nice heuristic that allowed a considerable improvement in the program's memory footprint, as well as the running time. The more formal name we gave it was Spatially Sensitive Hierarchical Clustering (SSHC), but ended up referring to it as Hierarchical Hierarchical Clustering which is funnier, and bett...
