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:[EMAIL PROTECTED]] > Sent: Tuesday, January 28, 2003 6:39 PM > To: [EMAIL PROTECTED] > 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 > > ______________________________________________ > [EMAIL PROTECTED] mailing list > http://www.stat.math.ethz.ch/mailman/listinfo/r-help > ------------------------------------------------------------------------------ ______________________________________________ [EMAIL PROTECTED] mailing list http://www.stat.math.ethz.ch/mailman/listinfo/r-help