[jira] Commented: (MAHOUT-165) Using better primitives hash for sparse vector for performance gains

["Sean Owen (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MAHOUT-165?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12789721#action_12789721 ] 

Sean Owen commented on MAHOUT-165:
----------------------------------

So this is done now right? SparseVector uses OpenIntDoubleMap now.

> Using better primitives hash for sparse vector for performance gains
> --------------------------------------------------------------------
>
>                 Key: MAHOUT-165
>                 URL: https://issues.apache.org/jira/browse/MAHOUT-165
>             Project: Mahout
>          Issue Type: Improvement
>          Components: Matrix
>    Affects Versions: 0.2
>            Reporter: Shashikant Kore
>            Assignee: Grant Ingersoll
>             Fix For: 0.3
>
>         Attachments: colt.jar, mahout-165-18nov-updated.patch, mahout-165-18nov.patch, MAHOUT-165-colt.patch, mahout-165-trove.patch, MAHOUT-165-updated.patch, MAHOUT-165-with-colt-module.patch, MAHOUT-165-with-colt.patch, mahout-165.patch, MAHOUT-165.patch, mahout-165.patch
>
>
> In SparseVector, we need primitives hash map for index and values. The present implementation of this hash map is not as efficient as some of the other implementations in non-Apache projects. 
> In an experiment, I found that, for get/set operations, the primitive hash of  Colt performance an order of magnitude better than OrderedIntDoubleMapping. For iteration it is 2x slower, though. 
> Using Colt in Sparsevector improved performance of canopy generation. For an experimental dataset, the current implementation takes 50 minutes. Using Colt, reduces this duration to 19-20 minutes. That's 60% reduction in the delay. 

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