[R] Curve Fitting Question - Newbie
Liaw, Andy
andy_liaw at merck.com
Wed Jan 29 01:51:02 CET 2003
If you don't need the parameters in the curve, it seems like
library(modreg)
lines(supsmu(1:1000, foo.dat), lwd=3)
gives a very reasonable result.
HTH,
Andy
> -----Original Message-----
> From: C Grant [mailto:cgrant02589 at yahoo.com]
> Sent: Tuesday, January 28, 2003 6:39 PM
> To: r-help at stat.math.ethz.ch
> Subject: [R] Curve Fitting Question - Newbie
>
>
> Hello, I have what should be an easy question. I'm a
> new r user and making the transition from menus to the
> command line so as to do batch processing of tons of
> data. One of my data streams needs to be detrended.
> It's a vector of numbers that follows a negative
> exponential decay. I need to fit a curve to it and use
> the residuals as an object. The data looks something
> like this:
>
> foo.dat <- (0.83 * exp(-0.017 * 1:1000) + 0.5) +
> rnorm(1000,0,0.05)
> plot(foo.dat, type = "l")
>
> That is an example the parameters for foo.dat change
> slightly. So, I need to fit a neg exponential curve to
> that type of data without specifying the parameters
> beforehand and save the residuals as an object. It
> will have to accomadate being in a loop.
>
> How can I do this?
>
> Regards, CG
>
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