[R] manual recreation of varConstPower using new fixed effects variables in nlme

[JJ]

Thanks much, Dr. Bates.  That helps.  Would you have
any comment on the other part of my other question
regarding the manual recreation of varConstPower
function using new fixed effects?  Im guessing I
obtain a singularity error because the additional
fixed effects may not alter the return value of my
function, fx.  The goal of attempting new variance
equations is to obtain in the end a variance function
that is of the form:

(d1 + (covariant)^d2)^2 + U,

where U is a random effect.

Thanks again.  John




--- Douglas Bates <bates at stat.wisc.edu> wrote:

> > PS:  Can anyone tell me what the reStruct
> parameter
> > means?  In looking at the verbose output, I obtain
> a
> > reStruct parameter value of -0.8352462 (this is
> for my
> > grouping factor for the random effect).  Does
> anyone
> > know what it means?  The actual value of my single
> > random effect is different, as is its variance.
> 
> IIRC it is the logarithm of the relative precision
> of the random effects.
> 
> 
>