[jira] [Updated] (SPARK-4823) rowSimilarities

["Debasish Das (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SPARK-4823?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Debasish Das updated SPARK-4823:
--------------------------------
    Attachment: MovieLensSimilarity Comparisons.pdf

The attached file shows the runtime comparison of row and column based flow on all items from MovieLens dataset on my local Macbook with 8 cores, 1 GB driver, 4 GB executor memory.

1e-2 is the threshold that's being set to both row based kernel flow and column based dimsum flow. 

Stage 24 - 35 is the row similarity flow. Total runtime ~ 20 s

Stage 64 is col similarity mapPartitions. Total runtime ~ 4.6 mins

This shows the power of blocking in Spark and I have not yet gone to gemv which will decrease the runtime further.

I updated the driver code in examples.mllib.MovieLensSimilarity  




> rowSimilarities
> ---------------
>
>                 Key: SPARK-4823
>                 URL: https://issues.apache.org/jira/browse/SPARK-4823
>             Project: Spark
>          Issue Type: Improvement
>          Components: MLlib
>            Reporter: Reza Zadeh
>         Attachments: MovieLensSimilarity Comparisons.pdf
>
>
> RowMatrix has a columnSimilarities method to find cosine similarities between columns.
> A rowSimilarities method would be useful to find similarities between rows.
> This is JIRA is to investigate which algorithms are suitable for such a method, better than brute-forcing it. Note that when there are many rows (> 10^6), it is unlikely that brute-force will be feasible, since the output will be of order 10^12.



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