7.00.02 - Background - Aster Analytics

Teradata Aster® Analytics Foundation User GuideUpdate 2

Aster Analytics
Release Number
Release Date
September 2017
Content Type
Programming Reference
User Guide
Publication ID
English (United States)

The Approximate Percentile function is based on an algorithm developed by Greenwald and Khanna. The function gives e-approximate quantile summaries of a set of N elements, where e is the error (the desired accuracy of the approximation). Given any rank r, an e-approximate summary returns a value whose rank r' is in the interval [r - e N , r + e N ]. The algorithm has a worst-case space requirement of O((1/e) * log(e N )).

When running the Approximate Percentile function, you specify e with the Error parameter.