Those are linear in the coefficients so try these: library(quantreg)
rq1 <- rq(demand ~ Time + I(Time^2), data = BOD, tau= 1:3/4); rq1 # or rq2 <- rq(demand ~ poly(Time, 2), data = BOD, tau = 1:3/4); rq2 On Tue, Jun 9, 2009 at 10:55 AM, despaired<meyfa...@uni-potsdam.de> wrote: > > Hi, > > I'm relatively new to R and need to do a quantile regression. Linear > quantile regression works, but for my data I need some quadratic function. > So I guess, I have to use a nonlinear quantile regression. I tried the > example on the help page for nlrq with my data and it worked. But the > example there was with a SSlogis model. Trying to write > > dat.nlrq <- nlrq(BM ~ I(Regen100^2), data=dat, tau=0.25, trace=TRUE) > > or > > dat.nlrq <- nlrq(BM ~ poly(Regen100^2), data=dat, tau=0.25, trace=TRUE) > > (I don't know the difference) both gave me the following error message: > > error in getInitial.default(func, data, mCall = as.list(match.call(func, : > no 'getInitial' method found for "function" objects > > Looking in getInitial, it must have to do something with the starting > parameters or selfStart model. But I have no idea, what this is and how I > handle this problem. Can anyone please help? > > Thanks a lot in advance! > -- > View this message in context: > http://www.nabble.com/Non-linear-regression-Quantile-regression-tp23944530p23944530.html > Sent from the R help mailing list archive at Nabble.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. > ______________________________________________ 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.