On Jun 12, 2011, at 20:25 , Diviya Smith wrote: > Hello there, > > I am trying to use R function NLS to analyze my data and one of the examples > in the documentation is - > > ## the nls() internal cheap guess for starting values can be sufficient: > > x <- -(1:100)/10 > y <- 100 + 10 * exp(x / 2) + rnorm(x)/10 > nlmod <- nls(y ~ Const + A * exp(B * x), trace=TRUE) > > plot(x,y, main = "nls(*), data, true function and fit, n=100") > curve(100 + 10 * exp(x / 2), col=4, add = TRUE) > lines(x, predict(nlmod), col=2) > > However, when I try to execute this - I get the following error- > > Error in nls(y ~ Const + A * exp(B * x), trace = TRUE) : > step factor 0.000488281 reduced below 'minFactor' of 0.000976562 > In addition: Warning message: > In nls(y ~ Const + A * exp(B * x), trace = TRUE) : > No starting values specified for some parameters > > Can someone propose how I can fix this error? Thanks.
Works for me. However, if you predefine some of the parameters, all bets are off, e.g. B <- 1000 example(nls) Try again with a clean workspace. -- Peter Dalgaard Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
