[ https://issues.apache.org/jira/browse/HIVE-3455?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13458446#comment-13458446 ]
Edward Capriolo commented on HIVE-3455: --------------------------------------- Good catch I set the input format to NLineInput create table data6 (name string, x int, y int) stored as inputformat 'org.apache.hadoop.mapred.lib.NLineInputFormat' outputformat 'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'; This did indeed mess produce the wrongresults. Nice catch. Will patch shortly. > ANSI CORR(X,Y) is incorrect > --------------------------- > > Key: HIVE-3455 > URL: https://issues.apache.org/jira/browse/HIVE-3455 > Project: Hive > Issue Type: Bug > Components: UDF > Affects Versions: 0.7.1, 0.8.0, 0.8.1, 0.9.0, 0.10.0 > Reporter: Maxim Bolotin > > A simple test with 2 collinear vectors returns a wrong result. > The problem is the merge of variances, file: > http://svn.apache.org/viewvc/hive/trunk/ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDAFCorrelation.java?revision=1157222&view=markup > lines: > 347: myagg.xvar += xvarB + (xavgA - xavgB) * (xavgA - xavgB) * myagg.count; > 348: myagg.yvar += yvarB + (yavgA - yavgB) * (yavgA - yavgB) * myagg.count; > the correct merge should be like this: > 347: myagg.xvar += xvarB + (xavgA - xavgB) * (xavgA - xavgB) / myagg.count * > nA * nB; > 348: myagg.yvar += yvarB + (yavgA - yavgB) * (yavgA - yavgB) / myagg.count * > nA * nB; -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira