The Java version of the t-digest was originally authored by Ted Dunning

A number of small but very helpful changes have been contributed by Adrien Grand (https://github.com/jpountz) to the Java version.

The C++ version herein is a derivative of the Java version.  It was written by Derrick R. Burns (https:://github.com/derrickburns).
The main modifications are 1) higher performance multi- t-digest merging and 2) faster quantile() and cdf() computation.