mahout-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Hudson (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MAHOUT-1837) Sparse/Dense Matrix analysis for Matrix Multiplication
Date Fri, 24 Jun 2016 22:17:16 GMT

    [ https://issues.apache.org/jira/browse/MAHOUT-1837?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15348777#comment-15348777
] 

Hudson commented on MAHOUT-1837:
--------------------------------

SUCCESS: Integrated in Mahout-Quality #3380 (See [https://builds.apache.org/job/Mahout-Quality/3380/])
MAHOUT-1837: fix incorrect <= threshold to > threshold to indicate a (apalumbo: rev
727e5be85c0326d9c009d9cdc361fe47ffa201ad)
* math-scala/src/test/scala/org/apache/mahout/math/scalabindings/MathSuite.scala
* spark/src/main/scala/org/apache/mahout/sparkbindings/drm/package.scala
* math-scala/src/main/scala/org/apache/mahout/math/scalabindings/MMul.scala
* math-scala/src/main/scala/org/apache/mahout/math/scalabindings/package.scala


> Sparse/Dense Matrix analysis for Matrix Multiplication
> ------------------------------------------------------
>
>                 Key: MAHOUT-1837
>                 URL: https://issues.apache.org/jira/browse/MAHOUT-1837
>             Project: Mahout
>          Issue Type: Improvement
>          Components: Math
>    Affects Versions: 0.12.0
>            Reporter: Andrew Palumbo
>            Assignee: Andrew Palumbo
>             Fix For: 0.13.0
>
>         Attachments: compareDensityTest.ods
>
>
> In matrix multiplication, Sparse Matrices can easily turn dense and bloat memory,  one
fully dense column and one fully dense row can cause a sparse %*% sparse operation have a
dense result.  
> There are two issues here one with a quick Fix and one a bit more involved:
>    #  in {{ABt.Scala}} use check the `MatrixFlavor` of the combiner and use the flavor
of the Block as the resulting Sparse or Dense matrix type:
> {code}
> val comb = if (block.getFlavor == MatrixFlavor.SPARSELIKE) {
>               new SparseMatrix(prodNCol, block.nrow).t
>             } else {
>               new DenseMatrix(prodNCol, block.nrow).t
>             }
> {code}
>  a simlar check needs to be made in the {{blockify}} transformation.
>  
>    #  More importantly, and more involved is to do an actual analysis of the resulting
matrix data in the in-core {{mmul}} class and use a matrix of the appropriate Structure as
a result. 



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message