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https://issues.apache.org/jira/browse/MATH-223?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Luc Maisonobe updated MATH-223:
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    Fix Version/s: 2.0

this should be fixed for 2.0

> QRDecomposition can easily be made to run about twice as fast
> -------------------------------------------------------------
>
>                 Key: MATH-223
>                 URL: https://issues.apache.org/jira/browse/MATH-223
>             Project: Commons Math
>          Issue Type: Improvement
>    Affects Versions: 1.2
>         Environment: Any
>            Reporter: John Mulcahy
>            Assignee: Luc Maisonobe
>            Priority: Minor
>             Fix For: 2.0
>
>         Attachments: QRDecompositionImpl.java
>
>
> The QRDecomposition will run much faster (about twice as fast) if the qr and 
> Q matrices are calculated as their transposes and the transposition is sorted 
> out in the getQ() method. Using the transposes allows the loops to iterate 
> over rows of the transposed matrices rather than columns. It might also be 
> useful to cache the Q matrix locally when it is generated in case there are 
> any subsequent calls to getQ() as this is the most expensive part of the 
> decomposition.

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