[jira] [Commented] (SPARK-1675) Make clear whether computePrincipalComponents centers data

2014-06-21 Thread Sean Owen (JIRA) 

[ 
https://issues.apache.org/jira/browse/SPARK-1675?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14039944#comment-14039944
 ] 

Sean Owen commented on SPARK-1675:
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Is this still valid? Looking at the code, PCA is computed as the SVD of the 
covariance matrix. The means implicitly don't matter. they are not explicitly 
subtracted, and do not matter. Or is there still a doc change desired?

> Make clear whether computePrincipalComponents centers data
> --
>
> Key: SPARK-1675
> URL: https://issues.apache.org/jira/browse/SPARK-1675
> Project: Spark
>  Issue Type: Improvement
>  Components: MLlib
>Affects Versions: 1.0.0
>Reporter: Sandy Ryza
>Assignee: Sandy Ryza
>




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[jira] [Commented] (SPARK-1675) Make clear whether computePrincipalComponents centers data

2014-05-14 Thread Xiangrui Meng (JIRA) 

[ 
https://issues.apache.org/jira/browse/SPARK-1675?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13998103#comment-13998103
 ] 

Xiangrui Meng commented on SPARK-1675:
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Centering in PCA should be the standard practice.

> Make clear whether computePrincipalComponents centers data
> --
>
> Key: SPARK-1675
> URL: https://issues.apache.org/jira/browse/SPARK-1675
> Project: Spark
>  Issue Type: Improvement
>  Components: MLlib
>Affects Versions: 1.0.0
>Reporter: Sandy Ryza
>Assignee: Sandy Ryza
>




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