I have been using nlsr() to fit s curves to Covid-19 data over the past few weeks and I have not had any issues.
Bernard Sent from my iPhone so please excuse the spelling!" > On May 13, 2020, at 5:16 PM, Abby Spurdle <spurdl...@gmail.com> wrote: > > Hi Christofer, > > This doesn't really answer your question. > But if the goal is to fit an S-shaped curve to data, with increased > flexibility... > (I'm assuming that's the goal). > > ...then I'd like to note the option of splines (or smoothing), subject > to shape constraints... > > My guess, is it's probably easier to model the inverse of a growth > curve this way, than to model the growth curve directly. > In which case, a 4-piece to 10-piece spline should give considerably flexibly. > > It's possible that Martin's package, cobs, can do this, but not sure, > I haven't tried it. > And there may be other R packages for fitting splines/smoothers to > data, subject to shape constraints. > > If not, I'm guessing it wouldn't be too difficult to implement, via > extensions to the quadprog package, for quadratic programming. > > >> On Wed, May 13, 2020 at 9:26 PM Christofer Bogaso >> <bogaso.christo...@gmail.com> wrote: >> >> Hi, >> >> Is there any R package to fit Richards' curve in the form of >> https://en.wikipedia.org/wiki/Generalised_logistic_function >> >> I found there is one package grofit, but currently defunct. >> >> Any pointer appreciated. >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> 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 -- To UNSUBSCRIBE and more, see > 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 -- To UNSUBSCRIBE and more, see 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.