Re: [R] Generating start values for nls

From: Gabor Grothendieck <ggrothendieck_at_gmail.com>
Date: Fri 20 Oct 2006 - 05:04:55 GMT

This has been discussed a number of times in the past, e.g. see this thread:

http://tolstoy.newcastle.edu.au/R/e2/help/06/09/0980.html

On 10/20/06, Paul Brewin <pebrewin@sdsc.edu> wrote:
> Dear R-listers,
>
> I would like to know if there is a way to programmatically generate
> parameter start values for the model y~(a*exp(b*x)+c*exp(d*x)) in R.
> I've scoured the help files and archives for nls() and similar searches,
> and have read Fox 2002 - the best advice has been to make estimates from
> a priori knowledge of the data. However, in the Matlab CurveFit tool,
> reliable start values are somehow estimated 'heuristically', as is
> claimed in their help files. Is there a similar R routine than may
> produce reasonable start values?
>
> Many thanks,
> Paul Brewin
>
> Paul E Brewin (PhD)
> Center for Research in Biological Systems
> University of California San Diego
> 9500 Gilman Drive MC 0505
> La Jolla CA, 92093-0505
> USA
>
> Ph: 858-822-0871
> Fax: 858-822-3610
>
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> and provide commented, minimal, self-contained, reproducible code.
>



R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Fri Oct 20 15:29:16 2006

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