[R] Inflection Points
rkoenker at uiuc.edu
Thu Jul 1 18:10:26 CEST 2004
take a look at predict.smooth.Pspline in the package pspline...
url: www.econ.uiuc.edu/~roger Roger Koenker
email rkoenker at uiuc.edu Department of Economics
vox: 217-333-4558 University of Illinois
fax: 217-244-6678 Champaign, IL 61820
On Jul 1, 2004, at 10:49 AM, Martin aus Chemnitz wrote:
> Some weeks ago I discovered R. Now, I have a somewhat complicated task
> and am not sure whether R is the right tool to solve it.
> I got data of several series or measurements where I have to find the
> two inflection points. I did a linear regression (with ^2 and ^3
> arguments), the problem there was that I had to look only at a very
> narrow band of measurement in order to get the approximation right at
> the essential point. (Maybe there is a better way than lm?)
> Now that I have an appromiated function, I need its inflection point,
> but I could not find any R function for that. Is there any? Or can
> anyone recommend a good (possibly free) mathematical programme?
> Maybe this could be helpful: All the measurements look like this and I
> marked the points of interest.
> / <--
> | <--
> Thank you very much for your help
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