acocac <acocac <at> gmail.com> writes: > > > Hi!! Im doing my graduated work in Onion Curves Growth with Nonlinear Models, > I'm amateur in R so i have doubt how i put or program next models, > > http://r.789695.n4.nabble.com/file/n3236748/96629508.png > > Also, i cant derivate for Gauss Model, and Richard Model dont have funtion, > If someone could help me, i was so grate, >
You need more help than we can give you here ... You need to use the ?nls function. I think if you are going to be doing a serious project fitting nonlinear growth models, you should probably learn or refresh enough calculus so that you can compute the derivatives yourself (R can do some small bit of analytic differentiation -- see ?D -- but it doesn't simplify at all, so the answers are quite often uglier than if you did the computation by hand). You don't absolutely need the derivative to use nls(), although it helps a lot. I would also suggest going to Google scholar and searching for 'nls "growth curve" Bates" to find some papers that have used this approach. If you need to post again, please read the posting guide and show us how far you have managed to get on your own. good luck, Ben Bolker ______________________________________________ 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.
