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Re: [Bug-gsl] gsl_sf_hyperg_1F1
From: |
Brian Gough |
Subject: |
Re: [Bug-gsl] gsl_sf_hyperg_1F1 |
Date: |
Fri, 11 Dec 2009 20:41:26 +0000 |
User-agent: |
Wanderlust/2.14.0 (Africa) Emacs/22.1 Mule/5.0 (SAKAKI) |
At Mon, 30 Nov 2009 15:26:11 +0100,
Weibin Li wrote:
> The output of above code shows an extremely large error. by increasing
> Ri, the relative error decreases. Is there any idea to fix this?
I've looked at the problem. Unfortunately I think it is just very
difficult to compute an accurate value in this region. The large
error reflects that. I have logged it at as bug at
https://savannah.gnu.org/bugs/index.php?28267
I could not find of any algorithm that gives an accurate value in this
region of parameters (a<<0, |a|>b>0, x>>0) , due to cancellation
errors in both the ordinary 1F1 series and Kummer transformed series.
If you know of one I would be glad to hear it.
--
Brian Gough
GNU Scientific Library -
http://www.gnu.org/software/gsl/