[
https://issues.apache.org/jira/browse/ACCUMULO-2494?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13946018#comment-13946018
]
Josh Elser commented on ACCUMULO-2494:
--------------------------------------
bq. Which version of Hadoop did you use?
Apache Hadoop 2.3.0. Looks like they bundle a commons-math3 (which contains a
{{org/apache/commons/math3/stat/descriptive/rank/Min}} but not
{{org/apache/commons/math/stat/descriptive/rank/Min}}). Taking a step to assume
that you're asking because you expected it to be provided by Hadoop.. haven't
we moved away from this due to the lessons learned from 1.5.0 (the original
emphasis that since we're using it directly, we should provide it directly)?
> Stat calculation of STDEV may be inaccurate
> -------------------------------------------
>
> Key: ACCUMULO-2494
> URL: https://issues.apache.org/jira/browse/ACCUMULO-2494
> Project: Accumulo
> Issue Type: Bug
> Components: client
> Reporter: Mike Drob
> Assignee: Mike Drob
> Fix For: 1.5.2, 1.6.0
>
>
> The math is sound, but it is susceptible to rounding errors. We should
> address that.
> See http://www.strchr.com/standard_deviation_in_one_pass and
> http://www.cs.berkeley.edu/~mhoemmen/cs194/Tutorials/variance.pdf
--
This message was sent by Atlassian JIRA
(v6.2#6252)
