RE: FW: roots of quartic equation (fwd)

[Matthias Winkler <Matthias dot Winkler at cern dot ch>]

Dear Andrew,

for what concerns our needs at the moment, we need it for real 
coefficients only.

Cheers,
Matthias

-- 

---------- Forwarded message ----------
Date: Wed, 24 Sep 2003 16:34:41 +0200
From: Marco Cattaneo <Marco.Cattaneo@cern.ch>
To: Matthias Winkler <Matthias.Winkler@cern.ch>
Subject: RE: FW: roots of quartic equation (fwd)

For what it's worth, our application uses only real coefficients

> -----Original Message-----
> From: Matthias Winkler 
> Sent: Wednesday, September 24, 2003 09:08
> To: Marco Cattaneo
> Subject: Re: FW: roots of quartic equation (fwd)
> 
> 
> Hello Marco!
> 
> Fyi, I got this mail today.
> 
> Cheers,
> Matthias
> 
> -- 
> 
> ---------- Forwarded message ----------
> Date: Tue, 23 Sep 2003 15:46:58 -0500 (CDT)
> From: Andrew Steiner <stein@physics.umn.edu>
> To: gsl-discuss@sources.redhat.com
> Cc: Matthias.Winkler@cern.ch
> Subject: Re: FW: roots of quartic equation (fwd)
> 
> Hello all!
> 
> 	Depending on the type of quartic you would like to solve
> (coefficients real or complex?), there are a couple options. For real
> coefficients, the C'ification of rrteq4.F would be pretty 
> straightforward,
> but for complex coefficients you need something more. On the topic of
> cubics, I have found that the GSL implementation of solutions to cubic
> equations tends to be a little more accurate (for random coefficients)
> than CERNLIB.
> 	It is also important to know what kind of quartics you have.
> Most of these routines fail miserably for sufficiently pathological
> choices of coefficients (i.e. small odd-powered coefficients).
> 
> Later,
> Andrew
> 
> ----------------------------------------------------------------------
>  Andrew W. Steiner                   Post-doctoral Research Associate
>  Nuclear Theory Group                University of Minnesota
>  Phone: 612-624-7872                 Fax: 612-624-4875
>  Email: stein@physics.umn.edu        URL: http://umn.edu/~stein178
> ----------------------------------------------------------------------
> 
> Brian Gough writes:
> > Matthias Winkler writes:
> >  > Dear GSL developers!
> >  >
> >  > May I forward you this question about the root of 
> quartic polynomial
> >  > equations in GSL. Will there be a dedicated 
> gsl_poly_solve_quartic
> >  > function?
> >
> > There is an empty space for it -- if someone writes a good
> > implementation it would certainly be added.
> >
> > I wasn't planning to write it myself though.
> >
> > If you specifically want the function within a fixed timescale, my
> > company can offer a GSL maintenance contract that would cover it.
> >
> > --
> > Brian
> 
> 
> 
>