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

["Grant Ingersoll (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MAHOUT-165?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12745415#action_12745415 ] 

Grant Ingersoll edited comment on MAHOUT-165 at 8/20/09 5:05 AM:
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http://acs.lbl.gov/~hoschek/colt-download/releases/license.html 

The clause for military use in HEP is unacceptable, unfortunately.  There is no way we could enforce that.  If we could use Colt w/o HEP, then we could use Colt.  Perhaps there is just a class or two from Colt that is ASL licensed that we can copy over and properly attribute and that doesn't have any dependencies on HEP?  

      was (Author: gsingers):
    http://acs.lbl.gov/~hoschek/colt-download/releases/license.html 

The clause for military use in HEP is unacceptable, unfortunately.  There is no way we could enforce that.  If we could use Colt w/o HEP, then we could use Colt.  Perhaps there is just a class or two from Colt that is ASL licensed that we can copy over and properly attribute?  
  
> 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
>             Fix For: 0.2
>
>         Attachments: 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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