[jira] [Issue Comment Edited] (MAHOUT-638) Stochastic svd's is not handling well all cases of sparse vectors

["Dmitriy Lyubimov (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MAHOUT-638?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13012230#comment-13012230 ] 

Dmitriy Lyubimov edited comment on MAHOUT-638 at 3/28/11 9:23 PM:
------------------------------------------------------------------

bq. I would drop most of the properties that specify versions. Defining a symbol that is used in one place doesn't really even save much.

I take it this is MAHOUT-622 comment?

      was (Author: dlyubimov):
    .bq I would drop most of the properties that specify versions. Defining a symbol that is used in one place doesn't really even save much.

I take it this is MAHOUT-622 comment?
  
> Stochastic svd's is not handling well all cases of sparse vectors 
> ------------------------------------------------------------------
>
>                 Key: MAHOUT-638
>                 URL: https://issues.apache.org/jira/browse/MAHOUT-638
>             Project: Mahout
>          Issue Type: Bug
>          Components: Math
>    Affects Versions: 0.5
>            Reporter: Dmitriy Lyubimov
>            Assignee: Dmitriy Lyubimov
>             Fix For: 0.5
>
>         Attachments: MAHOUT-638.patch
>
>
> The Mahout patch of the algorithm is not handling all types of sparse input efficiently. BtJob doesn't handle SequentialSparseVector in a way to pick only non-zero elements from initial input and QJob doesn't iterate over RandomAccessSparseVector correctly. With extremely sparse inputs (0.05% non-zero elements) that leads to a terrible inefficiency in the aforementioned jobs (QJob, BtJob).

--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira