Abstract
The k-means problem is perhaps the classical clustering problem and often synonymous with Lloyd's algorithm (1957). It has become clear that Hartigan's algorithm (1975) gives better results in almost all cases, Telgarsky-Vattani note a typical improvement of5\% -- 10\%. We point out that a very minor variation of Hartigan's method leads to another 2\% -- 5\% improvement; the improvement tends to become larger when either dimension or k increase.


