[jira] [Resolved] (MAHOUT-797) MapReduce SSVD: provide alternative B-pipeline per B=R' ^{-1} Y'A

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

     [ https://issues.apache.org/jira/browse/MAHOUT-797?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Dmitriy Lyubimov resolved MAHOUT-797.
-------------------------------------

    Resolution: Won't Fix

Ok, I am punting this for now, this is stale. While it is easy to do for the straightforward flow, it is not that easy for the power iterations flow, and my thought experiment indicates no bona fide performance improvements so far from this. 

I think i will attempt to revisit this in my spark solver where MR passes don't suffer form intermediate persistence or restart costs, so solver fusion within same step is not much of a problem there.

                
> MapReduce SSVD: provide alternative B-pipeline per B=R' ^{-1} Y'A
> -----------------------------------------------------------------
>
>                 Key: MAHOUT-797
>                 URL: https://issues.apache.org/jira/browse/MAHOUT-797
>             Project: Mahout
>          Issue Type: Improvement
>    Affects Versions: 0.5, 0.6
>            Reporter: Dmitriy Lyubimov
>            Assignee: Dmitriy Lyubimov
>             Fix For: Backlog
>
>         Attachments: MAHOUT-797.pdf
>
>   Original Estimate: 48h
>  Remaining Estimate: 48h
>
> Since alternative flow using Cholesky decomposition is extremely easy to add to existing computations of BB', I am thinking of just adding an option that chooses between B-pipeline with QR step and B-pipeline with Y'Y-Cholesky step. 
> Ongoing work and some initial code (Y'Y step) is here https://github.com/dlyubimov/mahout-commits/tree/MAHOUT-797.
> I also want to fix what's left unfixed in MAHOUT-638.

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