VAR() Variance UDF
------------------
Key: PIG-1150
URL: https://issues.apache.org/jira/browse/PIG-1150
Project: Pig
Issue Type: New Feature
Affects Versions: 0.5.0
Environment: UDF, written in Pig 0.5 contrib/
Reporter: Russell Jurney
Fix For: 0.5.0
I've implemented a UDF in Pig 0.5 that implements Algebraic and calculates
variance in a distributed manner, based on the AVG() builtin. It works by
calculating the count, sum and sum of squares, as described here:
http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Parallel_algorithm
Is this a worthwhile contribution? Taking the square root of this value using
the contrib SQRT() function gives Standard Deviation, which is missing from Pig.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
