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Re: GSL_Wigner_6J error


I think the convention is like that which relates the Racah W
coefficients and Wigner 6J symbols:

W(Ja Jb Jc Jd; Je Jf)  = pow(-1,(Ja+Jb+Jc+Jd)) / Ja Jb Je \
                                               \ Jd Jc Jf /

I think the simplest way to solve the problem is change the manual entry,
rather than the source code?

Regards,
Peter

*********************************************************

Peter Roche
Department of Applied Mathematics and Theoretical Physics,
University of Cambridge, Silver Street, Cambridge, CB3 9EW

email: p.j.p.roche@damtp.cam.ac.uk

*********************************************************

On 20 Nov 2002, Gerard Jungman wrote:

>
> Hi all. Sorry for the confusion here. I implemented this code,
> but I never looked closely at it. Is there a consensus about
> how it should work? It is definitely true that, as implemented,
> the function returns
>
> / Ja Jb Je \
> \ Jd Jc Jf /
>
> I'm not sure where this convention comes from, if anywhere.
>
> Should I change the interface or just change the documentation?
>
> Thanks.
>
> --
> G. Jungman
>
>
> On Mon, 2002-11-18 at 11:07, Peter Roche wrote:
> > Cheers, that solved the problem.
> >
> > Peter
> >
> > *********************************************************
> >
> > Peter Roche
> > Department of Applied Mathematics and Theoretical Physics,
> > University of Cambridge, Silver Street, Cambridge, CB3 9EW
> >
> > email: p.j.p.roche@damtp.cam.ac.uk
> >
> > *********************************************************
> >
> > On Thu, 14 Nov 2002, iwamae atsushi wrote:
> >
> > > Dear Peter
> > >
> > > One of my friend have found the same problem on the 6j symbol in GSL.
> > > In order to get the correct value, the order of J value should be written
> > > as
> > > follows,
> > >
> > > gsl_sf_coupling_6j(Ja, Jb, Jc, Jd, Je, Jf)
> > >
> > > { Ja, Jb, Je }
> > >   Jd, Jc, Jf
> > >
> > > The manual discription is not consistent.
> > > It says
> > > {Ja, Jb, Jc}
> > >  Jd, Je, Jf
> > > , but this order gives wrong value as you noticed
> > >
> > >
> > >
> > >
> > > Atsushi Iwamae
> > >
> > >
> > > >From: Peter Roche <P.J.P.Roche@damtp.cam.ac.uk>
> > > >To: gsl-discuss@sources.redhat.com
> > > >Subject: GSL_Wigner_6J error
> > > >Date: Wed, 13 Nov 2002 19:36:40 +0000 (GMT)
> > > >
> > > >
> > > >Dear All,
> > > >
> > > >I hope this isn't a repeat of an already dealt with problem. I have been
> > > >trying to use the GSL Wigner 6j coefficients routines
> > > >(gsl_sf_coupling_6j(2*ja, 2*jb, 2*jc, 2*jd,2*je,2*jf))  and have found,
> > > >I think, that some of the returned values from the GSL
> > > >routine are not correct, even for small input values.
> > > >
> > > >I have included a table showing, in the first column, the input
> > > >parameter values, the angular mometa (which are multiplied by 2 in my
> > > >actual program), the second column shows the 'correct' values, obtained
> > > >from another program/published tables, and the third column shows the
> > > >return values from the GSL routine.
> > > >
> > > >   Input       Correct values          GSL return
> > > >  (011100)     0.5773502691896257      0.0000000000000000
> > > >  (101101)     0.3333333333333335      0.0000000000000000
> > > >  (121101)     0.3333333333333334      0.0000000000000000
> > > >  (101101)     0.3333333333333335      0.0000000000000000
> > > >  (022200)     0.4472135954999579      0.0000000000000000
> > > >  (132201)     0.2581988897471612      0.0000000000000000
> > > >  (242202)     0.2000000000000000      0.0000000000000000
> > > >  (213302)     0.1690308509457034      0.0000000000000000
> > > >  (233302)     0.1690308509457033      0.0000000000000000
> > > >  (253302)     0.1690308509457033      0.0000000000000000
> > > >
> > > >
> > > >Has anyone encountered the same problems, or can explain the differences.
> > > >
> > > >Cheers,
> > > >Peter Roche
> > > >
> > > >*********************************************************
> > > >
> > > >Peter Roche
> > > >Department of Applied Mathematics and Theoretical Physics,
> > > >University of Cambridge, Silver Street, Cambridge, CB3 9EW
> > > >
> > > >email: p.j.p.roche@damtp.cam.ac.uk
> > > >
> > > >*********************************************************
> > >
> > >
> > > _________________________________________________________________
> > > $B%&%$%k%9%a!<%k!"LBOG%a!<%kBP:v$J$i(B MSN Hotmail http://www.hotmail.com/
> > >
> > >
> --
> Gerard Jungman <jungman@lanl.gov>
> Los Alamos National Laboratory
>
>


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