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From "Luc Maisonobe (JIRA)" <>
Subject [jira] Resolved: (MATH-375) Elementary functions in JDK are slower than necessary and not as accurate as they could be.
Date Sun, 05 Sep 2010 19:33:34 GMT


Luc Maisonobe resolved MATH-375.

    Resolution: Fixed

The asinacos patch fixing the errors identified by Jeff and adding the asin and acos functions
has been committed in the subversion repository as of r992872.
The tests for FastMath depending on the dfp library have also been added as dfp in now a package
in commons-math

Thanks for this contribution and the various fixes.

> Elementary functions in JDK are slower than necessary and not as accurate as they could
> -------------------------------------------------------------------------------------------
>                 Key: MATH-375
>                 URL:
>             Project: Commons Math
>          Issue Type: New Feature
>         Environment: JDK 1.4 - 1.6
>            Reporter: William Rossi
>             Fix For: 2.2
>         Attachments: asinacos-patch.txt.gz, atanpatch.txt.gz, FastMath.tar.gz,
> I would like to contribute improved versions on exp(), log(), pow(), etc.  to the project.
 Please refer to this discussion thread
> 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
> 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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