[R-sig-ME] nlme question...

[Murray Jorgensen]

Maybe you could tell us more about the data and why you wish to 
associate error components with b0 and b1 parameters? It just looks like 
a perfectly ordinary nonlinear model that might be fitted using the 
Gauss-Newton or partially linear methods using nls().

Murray Jorgensen

Jeffrey Harring wrote:
>  Hi all,
> 
> Can the algorithm in nlme handle a nonlinear function that is written as 
> a design matrix and linear coefficients like the following
> 
> The model is a nonlinear growth model with five time points: y = X*b +
> e, where design matrix X is defined as
> 
> X= |  1   0  |
>    |  1   1  |
>    |  1   k  |
>    |  1  2k  |
>    |  1  3k  |
> 
> and parameter vector b = (b0, b1). And where "k" is a parameter to be
> estimated. Of course I also want to estimate the intercept (b0), slope
> (b1). Error variances (e) with 5 free parameters and random effects
> covariance matrix  (2x2: for b0 and b1).
> 
> If anyone has concrete suggestions I would love to hear from you.
> 
> Thanks for your consideration,
> Jeff
> 
> 
> 
> 


-- 
Dr Murray Jorgensen      http://www.stats.waikato.ac.nz/Staff/maj.html
Department of Statistics, University of Waikato, Hamilton, New Zealand
Email: maj at waikato.ac.nz    majorgensen at ihug.co.nz      Fax 7 838 4155
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