[R] general Gauss-Newton or support for NSUR: contemporaneously correlated non-linear models
Spencer Graves
spencer.graves at pdf.com
Thu May 25 04:35:49 CEST 2006
Have you looked at nlme and the book Pinheiro and Bates (2000)
Mixed-Effects Models in S and S-Plus (Springer)? I'm not familiar with
"NSUR", but it sound like nlme might handle it very well.
hope this helps,
Spencer Graves
Thomas Wutzler wrote:
> Dear r-Help readers,
>
> 1) Is there support for NSUR in some R package yet?
> 2) Is there a general function of applying the Gauss-Newton or Marquard
> method, in which the function of calculating the partial derivatives can
> be specified by the user?
>
> Contemporaneously correlated non-linear models (NSUR) is a method to fit
> a system of non-linear equations.
>
> I want to use to fit several non-linear models at the same time, so that
> one the independent variable is alsway the sum of several other
> independent variable of other models.
> This procedure is described in detail by Parresol 2001. He used PROC
> MODEL by SAS to accomplish the task.
>
> If there is no support for NSUR yet, I would try to program a function
> by myself, although I only used very simple R-functins yet. The
> essential part is the fit the minimum of complex vector equation. This
> leads to my second question above. The function (as provided as an
> parameter) should accept a vector of model parameters and calculate the
> matrix of partial derivatives at this point in the parameter space.
>
>
> Thanks
> Thomas
>
> Parresol, B.R., 2001. Additivity of nonlinear biomass equations.
> Canadian Journal of Forest Research-Revue Canadienne De Recherche
> Forestiere 31, 865-878.
>
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