Return-Path: X-Original-To: apmail-accumulo-notifications-archive@minotaur.apache.org Delivered-To: apmail-accumulo-notifications-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id EDF7F105CE for ; Tue, 25 Mar 2014 17:04:22 +0000 (UTC) Received: (qmail 65232 invoked by uid 500); 25 Mar 2014 17:04:20 -0000 Delivered-To: apmail-accumulo-notifications-archive@accumulo.apache.org Received: (qmail 65184 invoked by uid 500); 25 Mar 2014 17:04:18 -0000 Mailing-List: contact notifications-help@accumulo.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: jira@apache.org Delivered-To: mailing list notifications@accumulo.apache.org Received: (qmail 65171 invoked by uid 99); 25 Mar 2014 17:04:18 -0000 Received: from arcas.apache.org (HELO arcas.apache.org) (140.211.11.28) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 25 Mar 2014 17:04:18 +0000 Date: Tue, 25 Mar 2014 17:04:17 +0000 (UTC) From: "Josh Elser (JIRA)" To: notifications@accumulo.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Commented] (ACCUMULO-2494) Stat calculation of STDEV may be inaccurate MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/ACCUMULO-2494?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13946793#comment-13946793 ] Josh Elser commented on ACCUMULO-2494: -------------------------------------- [~mdrob], ahh, gotcha. Thanks for taking care of this! > 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)