Re: GSL_Wigner_6J error

[Gerard Jungman <jungman at lanl dot gov>]

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