[R] fitting periodic 'sine wave' model

[Gabor Grothendieck]

Try

RSiteSearch("fit a sine")


On Tue, Jun 10, 2008 at 10:25 AM, Jon Loehrke <jloehrke at umassd.edu> wrote:
> I have been attempting to estimate the periodic contribution of an effect to
> some data but have not been able to fit a sine wave within R.
> It would be nice to start by being able to fit a sine wave with an amplitude
> and frequency.
>
> x<-seq(0,20,by=0.5)
> y<-2*sin(2*pi*.5*x) #amplitude =2, frequency=0.5
>
> # This failed to converge
> r<-nls(y ~ A*sin(2*pi*F*x), start=list(A = 1, F = 1), trace=T)
>
>
> # even this gave a max iteration error
> r<-nls(y ~ A*sin(2*pi*F*x), start=list(A = 1, F = .5), trace=T)
>
> I have a feeling I am approaching this incorrectly.  Thank you all very much
> for the guidance.
>
> Jon
> R 2.7.0
> mac os 10.5
>
>
> Jon Loehrke
> Graduate Research Assistant
> Department of Fisheries Oceanography
> School for Marine Science and Technology
> University of Massachusetts
> 200 Mill Road, Suite 325
> Fairhaven, MA 02719
> jloehrke at umassd.edu
> T 508-910-6393
> F 509-910-6396
>
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