Try it anyways -- maybe none of your constraints are active. On Wed, Mar 17, 2010 at 6:01 AM, Corrado <ct...@york.ac.uk> wrote: > Dear Gabor, dear R users, > > I had already read the betareg documentation. As far as I can understand > from the help, it does not allow for constrained regression. > > Regards > > > Gabor Grothendieck wrote: >> >> Check out the betareg package. >> >> On Tue, Mar 16, 2010 at 2:58 PM, Corrado <ct...@york.ac.uk> wrote: >> >>> >>> Dear R users, >>> >>> I have to fit the non linear regression: >>> >>> y~1-exp(-(k0+k1*p1+k2*p2+ .... +kn*pn)) >>> >>> where ki>=0 for each i in [1 .... n] and pi are on R+. >>> >>> I am using, at the moment, nls, but I would rather use a Maximum >>> Likelhood >>> based algorithm. The error is not necessarily normally distributed. >>> >>> y is approximately beta distributed, and the volume of data is medium to >>> large (the y,pi may have ~ 40,000 elements). >>> >>> I have studied the packages in the task views Optimisation and Robust >>> Statistical Methods, but I did look like what I was looking for was >>> there. >>> Maybe I am wrong. >>> >>> The nearest thing was nlrob, but even that does not allow for >>> constraints, >>> as far as I can understand. >>> >>> Any suggestion? >>> >>> Regards >>> >>> -- >>> Corrado Topi >>> PhD Researcher >>> Global Climate Change and Biodiversity >>> Area 18,Department of Biology >>> University of York, York, YO10 5YW, UK >>> Phone: + 44 (0) 1904 328645, E-mail: ct...@york.ac.uk >>> >>> ______________________________________________ >>> 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. >>> >>> > > > -- > Corrado Topi > PhD Researcher > Global Climate Change and Biodiversity > Area 18,Department of Biology > University of York, York, YO10 5YW, UK > Phone: + 44 (0) 1904 328645, E-mail: ct...@york.ac.uk > >
______________________________________________ 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.