The cpc package contains implementations of Kevin J. Lang’s CPC sketch. The
stored CPC sketch can consume about 40% less space than an HLL sketch of
comparable accuracy. Nonetheless, the HLL and CPC sketches have been
intentially designed to offer different tradeoffs so that, in fact, they
complement each other in many ways.
The hll module contains a set of very compact implementations of Phillipe
Flajolet’s HyperLogLog (HLL) sketch but with significantly improved error
behavior and excellent speed performance.