Re: [Bug-gsl] [bug #41837] bugs in gsl_sf_hyperg_U

[Raymond Rogers]

Hi Patrick,

    Actually I didn't think so; but upon examination it seems your 
right about the infinite being a correction (of some sort).   But 
calling the infinite sum with these values  is causing gamma to be 
called with a zero; which it shouldn't be.  Correcting the finite sum 
with an infinite one is not what I expected.
    Sigh..  I will look into what is going on in the infinite sum more 
carefully.   This is not the easiest code to follow :)  This time I will 
start altering the code to check my analysis, and write down the program 
flow.  (:

Ray


On 03/14/2014 02:29 PM, Patrick Alken wrote:
> Hi Ray,
>
>   Thanks for your report. If you have a correction you can upload it 
> to the bug tracker or just post it to this list.
>
> I don't know much about these functions but maybe someone else on the 
> list can check it. Based on that code snippet, it looks like it starts 
> off with a finite sum approximation to the true value, and then 
> refines that approximation with an infinite sum? It seems to pass in 
> the finite sum value to the infinite sum routine.
>
> But you're saying under certain argument conditions, its not necessary 
> to refine the initial approximation with the infinite sum?
>
> Patrick
>
> On 03/14/2014 12:24 PM, Raymond Rogers wrote:
> > I have added an analysis to the bug report.   Somebody needs to double
> > check it; I usually get things a little wrong the first time through.
> > If it should happen that my suggestion is valid; how and where do I
> > submit a correction?
> > Ray
> >
> > https://savannah.gnu.org/bugs/index.php?41837#comment4
> >
> > On 03/11/2014 06:24 PM, Patrick Alken wrote:
> > > Additional Item Attachment, bug #41837 (project gsl):
> > >
> > > File name: gsl_sf_hyperg_U_bug_report.cpp Size:0 KB
> > >
> > >
> > >       _______________________________________________________
> > >
> > > Reply to this item at:
> > >
> > >     <http://savannah.gnu.org/bugs/?41837>
> > >
> > > _______________________________________________
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