[
https://issues.apache.org/jira/browse/MAHOUT-653?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13016677#comment-13016677
]
Lance Norskog edited comment on MAHOUT-653 at 4/7/11 4:17 AM:
--------------------------------------------------------------
Use case: L1/L2 distances are not useful with very high dimensions. Fractional
L is more useful, and thus we need a fast but inaccurate pow() implementation.
pow() is around 3% off on average, and 20-40x faster than Math.pow().
Citations:
[http://arnetminer.org/viewpub.do?pid=303924]
[http://portal.acm.org/citation.cfm?id=656414]
Postscript version:
[Postscript|http://www.charuaggarwal.net/surprise.ps]
I found a PDF somewhere, but it is owned by the ACM.
was (Author: lancenorskog):
Use case: L1/L2 distances are not useful with very high dimensions.
Fractional L is more useful, and thus we need a fast but inaccurate pow()
implementation.
Citations:
[http://arnetminer.org/viewpub.do?pid=303924]
[http://portal.acm.org/citation.cfm?id=656414]
Postscript version:
[Postscript|http://www.charuaggarwal.net/surprise.ps]
I found a PDF somewhere, but it is owned by the ACM.
> Approximations to standard functions
> ------------------------------------
>
> Key: MAHOUT-653
> URL: https://issues.apache.org/jira/browse/MAHOUT-653
> Project: Mahout
> Issue Type: New Feature
> Reporter: Lance Norskog
> Attachments: MAHOUT-653.patch
>
>
> These give approximate versions of pow(value, exponent), exp(value), and
> natural log(value).
> log() and exp() stolen from:
> [http://martin.ankerl.com/2007/02/11/optimized-exponential-functions-for-java/]
> pow() stolen from:
> [http://martin.ankerl.com/2007/10/04/optimized-pow-approximation-for-java-and-c-c/]
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
