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https://issues.apache.org/jira/browse/MAHOUT-817?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13175867#comment-13175867
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Dmitriy Lyubimov commented on MAHOUT-817:
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bq. Thanks for merging Dmitriy. Is there anything you need from me at this
point?
I would always appreciate if you could poke CLI version and verify it
independently via matlab test for precision of computed singular values and V
output on a larger input.
(I am still working on reading Mahout files into R and merging with RHadoop,
when it's done i will be able to verify larger tests with R.)
-d
> Add PCA options to SSVD code
> ----------------------------
>
> Key: MAHOUT-817
> URL: https://issues.apache.org/jira/browse/MAHOUT-817
> Project: Mahout
> Issue Type: New Feature
> Affects Versions: 0.6
> Reporter: Dmitriy Lyubimov
> Assignee: Dmitriy Lyubimov
> Fix For: Backlog
>
> Attachments: MAHOUT-817.patch, SSVD-PCA options.pdf, ssvd-tests.R,
> ssvd.R, ssvd.m
>
>
> It seems that a simple solution should exist to integrate PCA mean
> subtraction into SSVD algorithm without making it a pre-requisite step and
> also avoiding densifying the big input.
> Several approaches were suggested:
> 1) subtract mean off B
> 2) propagate mean vector deeper into algorithm algebraically where the data
> is already collapsed to smaller matrices
> 3) --?
> It needs some math done first . I'll take a stab at 1 and 2 but thoughts and
> math are welcome.
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