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Hudson commented on MAHOUT-1185: -------------------------------- Integrated in Mahout-Quality #1945 (See [https://builds.apache.org/job/Mahout-Quality/1945/]) MAHOUT-1185 ensure last item's value is counted in average (not diffs) (Revision 1463463) Result = SUCCESS srowen : http://svn.apache.org/viewcvs.cgi/?root=Apache-SVN&view=rev&rev=1463463 Files : * /mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/recommender/slopeone/MemoryDiffStorage.java > MemoryDiffStorage.class has a bug for slope one algorithm which could cause > incorrect recommendation results > ------------------------------------------------------------------------------------------------------------ > > Key: MAHOUT-1185 > URL: https://issues.apache.org/jira/browse/MAHOUT-1185 > Project: Mahout > Issue Type: Bug > Components: Collaborative Filtering > Affects Versions: 0.7 > Environment: Ubuntu > Reporter: Cunlu Zou > Assignee: Sean Owen > Priority: Minor > Fix For: 0.8 > > Attachments: MemoryDiffStorage.patch, MemoryDiffStorage.patch > > Original Estimate: 10m > Remaining Estimate: 10m > > The function processOneUser(long averageCount, long userID) in the > MemoryDiffStorage.class file contains a bug for calculating the itemAverage. > Since the function tried to calculate the average difference among items (in > a nested loop) and also the average individual item preference value in the > same loop (the loop only from 0 to length-2, *for (int i = 0; i < length - 1; > i++)*), the itemAverage variable does not count the last item's preference > value for every users which could lead to an incorrect recommendation results. -- 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