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Posted to issues@commons.apache.org by "Luc Maisonobe (JIRA)" <ji...@apache.org> on 2010/09/18 17:44:33 UTC
[jira] Created: (MATH-417) improve performance of Percentile
improve performance of Percentile
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Key: MATH-417
URL: https://issues.apache.org/jira/browse/MATH-417
Project: Commons Math
Issue Type: Improvement
Affects Versions: 2.1
Reporter: Luc Maisonobe
Fix For: 2.2
The 2.1 implementation of Percentile sorts the sample array each time its evaluate method is called.
When a lot of different percentiles are to be computed for the same sample, this unduces a lot of sorting work that could be avoided.
When only one percentile is desired, a complete sort is also a waste of efforts as it runs in O(n ln(n)) when only a selection in O(n) would be sufficient.
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[jira] Resolved: (MATH-417) improve performance of Percentile
Posted by "Luc Maisonobe (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/MATH-417?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Luc Maisonobe resolved MATH-417.
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Resolution: Fixed
Fixed in subversion repository as of r1006299 for branch 2.x and as of r1006301 for trunk
> improve performance of Percentile
> ---------------------------------
>
> Key: MATH-417
> URL: https://issues.apache.org/jira/browse/MATH-417
> Project: Commons Math
> Issue Type: Improvement
> Affects Versions: 2.1
> Reporter: Luc Maisonobe
> Fix For: 2.2
>
>
> The 2.1 implementation of Percentile sorts the sample array each time its evaluate method is called.
> When a lot of different percentiles are to be computed for the same sample, this unduces a lot of sorting work that could be avoided.
> When only one percentile is desired, a complete sort is also a waste of efforts as it runs in O(n ln(n)) when only a selection in O(n) would be sufficient.
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