On 17 March 2010 14:22, Gabor Grothendieck <ggrothendi...@gmail.com> wrote: > Contact the maintainer regarding problems with the package. Not sure > if this is acceptable but if you get it to run you could consider just > dropping the variables from your model that correspond to active > constraints. > > Also try the maxLik package. You will have to define the likelihood > yourself but it does support constraints.
Yes. And specifying the likelihood function is probably (depending on your distributional assumptions) not too complicated. BTW: Even if your y follows a beta distribution, it does not mean that your error term also follows a beta distribution. And it the distribution of the error term which is crucial for specifying the likelihood function. /Arne > On Wed, Mar 17, 2010 at 9:07 AM, Corrado <ct...@york.ac.uk> wrote: >> Dear Gabor, >> >> 1) The constraints are active, at least from a formal point view. >> 3) I have tried several times to run betareg.fit on the data, and the only >> thing I can obtain is the very strange error: >> >> Error in dimnames(x) <- dn : length of 'dimnames' [2] not equal to array >> extent >> >> The error is strange because, because the function dimnames is not called >> anywhere. >> Regards >> >> Gabor Grothendieck wrote: >>> >>> 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 >>>> >>>> >>>> >> >> >> -- >> 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. > -- Arne Henningsen http://www.arne-henningsen.name ______________________________________________ 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.