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https://issues.apache.org/jira/browse/MATH-738?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13483917#comment-13483917
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Sébastien Brisard edited comment on MATH-738 at 10/25/12 6:10 AM:
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Hi Thomas,
thanks for proposing your help. Please wait a little, as I have already
implemented some more methods, not yet committed.
For the time being, I'm working on a Java app to automatically assess the
accuracy of implementation of special functions. I need to write a small README
to explain how it works, then I'll commit the whole lot. I also have
reimplemented logBeta. I will provide all these soon, but I am drowned in work
for the time being.
I'll try to commit next weekend. Thanks for your patience!
BTW: be careful with TOMS code, which is copyrighted. I based my
implementations on the NSWC library, which is very (very) similar, as it's the
same author, but is not copyrighted.
was (Author: celestin):
Hi Thomas,
thanks for proposing your help. Please wait a little, as I have already
implemented some more methods, not yet committed.
For the time being, I'm working on a Java app to automatically assess the
accuracy of implementation of special functions. I need to write a small README
to explain how it works, then I'll commit the whole lot. I also have
reimplemented logBeta. I will provide all these soon, but I am drowned in work
for the time being.
Thanks for your patience!
> Incomplete beta function I(x, a, b) is inaccurate for large values of a
> and/or b
> --------------------------------------------------------------------------------
>
> Key: MATH-738
> URL: https://issues.apache.org/jira/browse/MATH-738
> Project: Commons Math
> Issue Type: Bug
> Affects Versions: 3.0
> Reporter: Sébastien Brisard
> Assignee: Sébastien Brisard
> Labels: special-functions
> Fix For: 3.1, 4.0
>
>
> This was first reported in MATH-718. The result of the current implementation
> of the incomplete beta function I(x, a, b) is inaccurate when a and/or b are
> large-ish.
> I've skimmed through [slatec|http://www.netlib.org/slatec/fnlib/betai.f],
> GSL,
> [Boost|http://www.boost.org/doc/libs/1_38_0/libs/math/doc/sf_and_dist/html/math_toolkit/special/sf_beta/ibeta_function.html]
> as well as NR. At first sight, neither uses the same method to compute this
> function. I think [TOMS-708|http://www.netlib.org/toms/708] is probably the
> best option.
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