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.
