Hi, Bert Thanks for your reply.
I am fitting a logistic does response model with 3 parameters as : y=a/(1+(x/x0)b), I have many sets of data. I can fit each of them for the model. but I want them shared the parameter x0 and b, but varied for each a. I don't think it is a statistics problem. It is a typical global curve fitting problem with shared parameters. And I know how to do it by many other software. But since I am trying to use R, I am wondering is there any package or method to do it in R? Thanks! Jianling On 9 September 2015 at 10:16, Bert Gunter <bgunter.4...@gmail.com> wrote: > Jianling: > > 1. What models are you trying to fit? Details matter, and it is > impossible to give a good answer without specifics. > > 2. In general terms, to do this one combines all the data and allows > for "appropriate" changes in the model parameters for the different > groups. For example, different intercepts, rate constants, etc. This > is where the specifics matter. > > 3. This is really more a statistics than an R question, and you would > probably do better to pursue these issues either with a local > statistical resource or on a statistics site, like > stats.stackexchange.com. > > Cheers, > Bert > Bert Gunter > > "Data is not information. Information is not knowledge. And knowledge > is certainly not wisdom." > -- Clifford Stoll > > > On Wed, Sep 9, 2015 at 9:04 AM, Jianling Fan <fanjianl...@gmail.com> wrote: >> Hello all, >> >> I am trying to fit my data to a nls model. I have many sets of data >> and each can fit well for the curve. but I want to fit them at once by >> sharing 2 of 3 parameters of the model. I know it is a typical global >> curve fitting problem, but I don't know how to do it by R? >> >> Does anyone know any package for this?? >> >> Thanks a lot! >> >> >> Julian >> >> ______________________________________________ >> 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. -- Jianling Fan 樊建凌 ______________________________________________ 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.
