[R] Constrained non linear regression using ML

[Corrado]

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 <ct529 at 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 <ct529 at 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: ct529 at york.ac.uk
>>>>
>>>> ______________________________________________
>>>> R-help at 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: ct529 at 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: ct529 at york.ac.uk