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Posted to dev@mahout.apache.org by "jiraposter@reviews.apache.org (Commented) (JIRA)" <ji...@apache.org> on 2011/12/01 09:33:42 UTC
[jira] [Commented] (MAHOUT-880) Add some matrix method(like
addition, subtraction, norm ... etc) to DistributedRowMatrix
[ https://issues.apache.org/jira/browse/MAHOUT-880?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13160733#comment-13160733 ]
jiraposter@reviews.apache.org commented on MAHOUT-880:
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bq. On 2011-11-29 19:56:51, Jake Mannix wrote:
bq. > trunk/core/src/main/java/org/apache/mahout/math/hadoop/MatrixRowAverageJob.java, line 116
bq. > <https://reviews.apache.org/r/2955/diff/1/?file=60411#file60411line116>
bq. >
bq. > This will force a huge bottleneck of one reducer, will it not?
Thanks for the feedback Jake, it's really appreciated! I think the load will be distributed somewhat by the combiner at each node. Do you still think this will cause too much of a bottleneck?
Do you have any suggestions for a better way to implement this?
- Raphael
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On 2011-11-29 18:44:49, Raphael Cendrillon wrote:
bq.
bq. -----------------------------------------------------------
bq. This is an automatically generated e-mail. To reply, visit:
bq. https://reviews.apache.org/r/2955/
bq. -----------------------------------------------------------
bq.
bq. (Updated 2011-11-29 18:44:49)
bq.
bq.
bq. Review request for Ted Dunning, Jake Mannix and Sebastian Schelter.
bq.
bq.
bq. Summary
bq. -------
bq.
bq. Jobs for matrix-vector addition, covariance matrix calculation and row average calculation in DistributedRowMatrix
bq.
bq.
bq. This addresses bug MAHOUT-880.
bq. https://issues.apache.org/jira/browse/MAHOUT-880
bq.
bq.
bq. Diffs
bq. -----
bq.
bq. trunk/core/src/main/java/org/apache/mahout/math/hadoop/DistributedRowMatrix.java 1206431
bq. trunk/core/src/main/java/org/apache/mahout/math/hadoop/MatrixCovarianceJob.java PRE-CREATION
bq. trunk/core/src/main/java/org/apache/mahout/math/hadoop/MatrixRowAverageJob.java PRE-CREATION
bq. trunk/core/src/main/java/org/apache/mahout/math/hadoop/MatrixVectorAdditionJob.java PRE-CREATION
bq. trunk/core/src/test/java/org/apache/mahout/math/hadoop/TestDistributedRowMatrix.java 1206431
bq.
bq. Diff: https://reviews.apache.org/r/2955/diff
bq.
bq.
bq. Testing
bq. -------
bq.
bq. Junit tests for each job
bq.
bq.
bq. Thanks,
bq.
bq. Raphael
bq.
bq.
> Add some matrix method(like addition, subtraction, norm ... etc) to DistributedRowMatrix
> ----------------------------------------------------------------------------------------
>
> Key: MAHOUT-880
> URL: https://issues.apache.org/jira/browse/MAHOUT-880
> Project: Mahout
> Issue Type: New Feature
> Components: Math
> Affects Versions: 0.6
> Reporter: Wangda Tan
> Priority: Minor
> Labels: DistributedRowMatrix
> Attachments: MAHOUT-880.patch
>
>
> I'm a new to Mahout, I didn't find some basic matrix functions. This make users cannot do many tasks by CLI or API, if user get some result through existing map-reduce matrix operation (like svd), he cannot do farther steps. I make a list for it:
> 1) Addition, Subtraction
> 2) Norm (like norm-1, norm-2, norm-frobenius)
> 3) Matrix compare
> 4) Get lower triangle, upper triangle and diagonal
> 5) Get identity and zero matrix
> 6) Put two or matrix to together: A = [A1, A2]
> 7) More linear equations solver method, like Gaussian elimination (maybe it's hard to implement)
> 8) import and export CSV, ARFF ... (this will very useful when user want to reuse result from or to other applications like MATLAB)
> I want to know is there any plan to do this, if so, I can make some efforts to implement these.
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