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Re: [Help-gsl] Re: Re: non-linear least squares fitting
From: |
Barrett C. Foat |
Subject: |
Re: [Help-gsl] Re: Re: non-linear least squares fitting |
Date: |
Thu, 6 Dec 2007 08:25:20 -0600 |
User-agent: |
KMail/1.9.3 |
I guess that I misunderstood. I have always used analytical partial
derivatives. I am kind of surprised that numerical partial derivatives
work. However, if the optimization converges without errors, it must be a
good enough approximation for your function. In my experience, this
package fails to converge if you do something wrong with the derivatives.
Barrett Foat
On Thursday 06 December 2007 03:21, Richard Henwood wrote:
> <posted & mailed>
>
> Barrett Foat wrote:
> >> I implement fdf using numerical partial differentiation of f.
> >>
> >> This method (numerical partial differentials) appeared to work;
> >> is this a reasonable approach?
> >
> > Yes, the df and fdf functions need to caluclate the numerical partial
> > derivatives given the current values of the arguments (vector x in the
> > docs) and your independent variable data.
> >
> > To my knowledge, the approach you took is the only reasonable
> > approach.
>
> Good.
>
> Is the only alternative approach to use the analytic partial derivatives
> in df and fdf?
>
> My reading is that this approach is used in the example given in the GSL
> manual example.
>
> r,
>
>
>
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- [Help-gsl] non-linear least squares fitting, Jay Howard, 2007/12/04
- Re: [Help-gsl] non-linear least squares fitting, Barrett C. Foat, 2007/12/04
- Re: [Help-gsl] non-linear least squares fitting, Jay Howard, 2007/12/04
- Re: [Help-gsl] non-linear least squares fitting, Barrett C. Foat, 2007/12/05
- Re: [Help-gsl] non-linear least squares fitting, Jay Howard, 2007/12/05
- Re: [Help-gsl] non-linear least squares fitting, Barrett Foat, 2007/12/05
- Re: [Help-gsl] non-linear least squares fitting, Jay Howard, 2007/12/05
- [Help-gsl] Re: non-linear least squares fitting, Richard Henwood, 2007/12/05
- Re: [Help-gsl] Re: non-linear least squares fitting, Barrett Foat, 2007/12/05
- [Help-gsl] Re: Re: non-linear least squares fitting, Richard Henwood, 2007/12/06
- Re: [Help-gsl] Re: Re: non-linear least squares fitting,
Barrett C. Foat <=
- Re: [Help-gsl] Re: Re: non-linear least squares fitting, Jay Howard, 2007/12/07
- Re: [Help-gsl] Re: Re: non-linear least squares fitting, Barrett C. Foat, 2007/12/10