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Posted to issues@spark.apache.org by "Apache Spark (JIRA)" <ji...@apache.org> on 2015/01/26 08:37:34 UTC

[jira] [Commented] (SPARK-5406) LocalLAPACK mode in RowMatrix.computeSVD should have much smaller upper bound

    [ https://issues.apache.org/jira/browse/SPARK-5406?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14291539#comment-14291539 ] 

Apache Spark commented on SPARK-5406:
-------------------------------------

User 'hhbyyh' has created a pull request for this issue:
https://github.com/apache/spark/pull/4200

> LocalLAPACK mode in RowMatrix.computeSVD should have much smaller upper bound
> -----------------------------------------------------------------------------
>
>                 Key: SPARK-5406
>                 URL: https://issues.apache.org/jira/browse/SPARK-5406
>             Project: Spark
>          Issue Type: Bug
>          Components: MLlib
>    Affects Versions: 1.2.0
>         Environment: centos, others should be similar
>            Reporter: yuhao yang
>            Priority: Minor
>   Original Estimate: 2h
>  Remaining Estimate: 2h
>
> In RowMatrix.computeSVD, under LocalLAPACK mode, the code would invoke brzSvd. Yet breeze svd for dense matrix has latent constraint. In it's implementation:
>       val workSize = ( 3
>         * scala.math.min(m, n)
>         * scala.math.min(m, n)
>         + scala.math.max(scala.math.max(m, n), 4 * scala.math.min(m, n)
>           * scala.math.min(m, n) + 4 * scala.math.min(m, n))
>       )
>       val work = new Array[Double](workSize)
> as a result, column num must satisfy 7 * n * n + 4 * n < Int.MaxValue
> thus, n < 17515.
> This jira is only the first step. If possbile, I hope spark can handle matrix computation up to 80K * 80K.



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