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https://issues.apache.org/jira/browse/MAHOUT-880?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13159439#comment-13159439
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[email protected] commented on MAHOUT-880:
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bq. On 2011-11-29 08:41:06, Sebastian Schelter wrote:
bq. >
trunk/core/src/main/java/org/apache/mahout/math/hadoop/MatrixCovarianceJob.java,
line 119
bq. > <https://reviews.apache.org/r/2955/diff/1/?file=60410#file60410line119>
bq. >
bq. > Don't we have to center the rows for covariance? Am I missing
something or do you assume that the data is already centered?
Thank you for the feedback Sebastian.
You're right, we first need to center the rows. I should rename this Job to
remove confusion. In general it is just meant to compute x.transpose().times(x).
- Raphael
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On 2011-11-29 05:40:30, 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 05:40:30)
bq.
bq.
bq. Review request for Jake Mannix.
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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