Thanks to all for your help! That works! Orange
On Sat, Apr 7, 2012 at 7:25 PM, Gabor Grothendieck <ggrothendi...@gmail.com>wrote: > Yes, I had fixed that on my end but didn't notice I had copied the old > version. I think its obvious enough that anyone will fix it > themselves. Regards. > > On Sat, Apr 7, 2012 at 7:23 PM, Rolf Turner <rolf.tur...@xtra.co.nz> > wrote: > > > > One other minor glitch I just noticed: > > > > x <- seq_along(x) > > > > should read > > > > x <- seq_along(y) > > > > cheers, > > > > Rolf > > > > > > On 08/04/12 10:08, Gabor Grothendieck wrote: > >> > >> On Sat, Apr 7, 2012 at 3:58 PM, Gabor Grothendieck > >> <ggrothendi...@gmail.com> wrote: > >>> > >>> On Fri, Apr 6, 2012 at 9:42 PM, help ly<help.ly2...@gmail.com> wrote: > >>>> > >>>> Dear All, > >>>> > >>>> I would like to make a quadratic with a plateau model in R. Is there a > >>>> package in R doing this? The bentcableAR package seems won't work. > >>>> > >>>> The link below describes what I am looking for in R exactly: > >>>> > >>>> > http://support.sas.com/documentation/cdl/en/statug/63033/HTML/default/viewer.htm#statug_nlin_sect033.htm > >>>> > >>> Use nls directly: > >>> > >>> y<- c(0.46, 0.47, 0.57, 0.61, 0.62, 0.68, 0.69, 0.78, 0.7, 0.74, > >>> 0.77, 0.78, 0.74, 0.8, 0.8, 0.78) > >>> x<- seq_along(x) > >>> > >>> Mean<- function(x, alpha, beta, gamma) { > >>> pmin(alpha + beta*x + gamma*x*x, alpha - beta^2/(4 * gamma)) > >>> } > >>> fm<- nls(y ~ Mean(x, alpha, beta, gamma), start = list(alpha = 0.45, > >>> beta = 0.05, gamma = -0.0025)) > >>> fm > >>> summary(fm) > >>> > >>> plot(y ~ x) > >>> lines(fitted(fm) ~ x) > >> > >> It was pointed out to me offline that Mean as defined above is not > >> identical to the definition in the poster's link. Here is a revision: > >> > >> y<- c(0.46, 0.47, 0.57, 0.61, 0.62, 0.68, 0.69, 0.78, 0.7, 0.74, > >> 0.77, 0.78, 0.74, 0.8, 0.8, 0.78) > >> x<- seq_along(x) > >> > >> Mean<- function(x, alpha, beta, gamma) { > >> ifelse(x< -beta/(2 * gamma), alpha + beta*x + gamma*x*x, > >> alpha - beta^2/(4 * gamma)) > >> } > >> fm<- nls(y ~ Mean(x, alpha, beta, gamma), start = list(alpha = 0.45, > >> beta = 0.05, gamma = -0.0025)) > >> fm > >> summary(fm) > >> > >> plot(y ~ x) > >> lines(fitted(fm) ~ x) > >> with(as.list(coef(fm)), abline(v = -beta/(2 * gamma))) > >> > >> > > > > > > -- > Statistics & Software Consulting > GKX Group, GKX Associates Inc. > tel: 1-877-GKX-GROUP > email: ggrothendieck at gmail.com > -- Thanks so much! Orange help.ly2...@gmail.com [[alternative HTML version deleted]] ______________________________________________ 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.
