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Re: Scilab is now GPL v2 compatible - as the site claims
From: |
Sergei Steshenko |
Subject: |
Re: Scilab is now GPL v2 compatible - as the site claims |
Date: |
Sun, 21 Sep 2008 00:40:17 -0700 (PDT) |
--- On Sun, 9/21/08, Marc Normandin <address@hidden> wrote:
> From: Marc Normandin <address@hidden>
> Subject: Re: Scilab is now GPL v2 compatible - as the site claims
> To: "address@hidden" <address@hidden>
> Cc: "address@hidden" <address@hidden>
> Date: Sunday, September 21, 2008, 12:19 AM
> Sergei Steshenko wrote:
> > Anyway, frep2tf has a subtle, though not serious,
> flaw.
> >
> > IIRC, it uses sum of abs deviations rather than sum of
> squares of abs
> > deviations as its error metric. I mean, strictly
> saying, it's not least
> > squares approximation as it claims.
>
> From your description, it sounds like the the method is
> reasonable,
> though perhaps not what people would expect; thus, it's
> the
> documentation that's incorrect. They've simply
> chosen a "robust"
> estimator in favor of the the minimum mean square approach,
> which one
> can argue is sensitive to noise.
>
> Regards,
> Marc
>
> --
Again, I do not understand all the details, but, I think, they are
solving a system of linear equations based on true least squares approach
(this happens in each iteration), but they choose the best solution after
a number of iteration based on the sum of abs deviations, not on the sum
of squares of abs deviations.
So, I think, their approach has an internal contradiction.
Regards,
Sergei.
- Scilab is now GPL v2 compatible - as the site claims, Sergei Steshenko, 2008/09/18
- Re: Scilab is now GPL v2 compatible - as the site claims, bharat pathak, 2008/09/21
- Re: Scilab is now GPL v2 compatible - as the site claims, Sergei Steshenko, 2008/09/21
- Re: Scilab is now GPL v2 compatible - as the site claims, Francesco Potorti`, 2008/09/21
- Re: Scilab is now GPL v2 compatible - as the site claims, Søren Hauberg, 2008/09/21
Re: Scilab is now GPL v2 compatible - as the site claims, David Bateman, 2008/09/21