[R] Generating start values for nls

[Gabor Grothendieck]

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 at 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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