[R] Inflection Points

[roger koenker]

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:

> 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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