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Posted to issues@commons.apache.org by "Luc Maisonobe (JIRA)" <ji...@apache.org> on 2010/07/25 21:26:51 UTC
[jira] Commented: (MATH-375) Elementary functions in JDK are slower
than necessary and not as accurate as they could be.
[ https://issues.apache.org/jira/browse/MATH-375?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12892134#action_12892134 ]
Luc Maisonobe commented on MATH-375:
------------------------------------
I finally found some time to look at this proposal.
It is very impressive and I really want to include it.
As the code is rather long and has been developed outside of the Apache Software Foundation, could you send a signed Software Grant to the foundation (see [http://www.apache.org/licenses/#grants]) ? As you will see, the softaware grant is simply a license you grant, the intellectual property remains yours.
The best way would be to have it sent by fax or by mail with a detached gpg signature. Please refer to this Jira issue and the attached patch you already submitted.
Thanks a lot for this contribution.
> Elementary functions in JDK are slower than necessary and not as accurate as they could be.
> -------------------------------------------------------------------------------------------
>
> Key: MATH-375
> URL: https://issues.apache.org/jira/browse/MATH-375
> Project: Commons Math
> Issue Type: New Feature
> Environment: JDK 1.4 - 1.6
> Reporter: William Rossi
> Attachments: FastMath.tar.gz
>
>
> I would like to contribute improved versions on exp(), log(), pow(), etc. to the project. Please refer to this discussion thread http://markmail.org/message/zyeoguw6gwtofm62.
> I have developed over the past year a set of elementary functions similar to those in java.lang.Math, but with the following characteristics:
> * Higher performance.
> * Better accuracy. Results are accurate to slightly more that +/- 0.5 ULP.
> * Pure Java. The standard Math class is impleneted via JNI, and thus takes a performance hit.
> Note that some functions such as exp are nearly twice as fast in my implementation. I've seen it 3 times faster on different processors. The preformance varies by the relative speed of calculation vs memory lookups.
> The functions are implemented as tables of values in extra precision (approx 70 bits), and then interpolated with a minimax polynomial.
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