[R] Inflection Points

[cornulier]

does locpoly in package KernSmooth help?


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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             Thomas Cornulier
Centre d'Etudes Biologiques de Chizé - CNRS
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