Background - Aster Analytics

Teradata Aster® Analytics Foundation User GuideUpdate 2

Product
Aster Analytics
Release Number
7.00.02
Published
September 2017
Language
English (United States)
Last Update
2018-04-17
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uce1497542673292.ditamap
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dita:id
B700-1022
lifecycle
previous
Product Category
Software

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.