Re: [R] Inflection Points

From: roger koenker <rkoenker_at_uiuc.edu>
Date: Fri 02 Jul 2004 - 02:10:26 EST

take a look at predict.smooth.Pspline in the package pspline...

url:	www.econ.uiuc.edu/~roger        	Roger Koenker
email	rkoenker@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:

> Hi!
>
> 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
>
> Martin
>
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R-help@stat.math.ethz.ch mailing list
https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Jul 02 02:13:51 2004

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