Hi Tony,

Unfortunately I never did solve this problem.  I experimented endlessly
with all sorts of combinations of correlation structures available with
lme.  Unless someone reads this will a wonderful solution to replicate the
unstructure structure analysis from SAS I can't help.  The compound
symmetry correlation structure was the only that really matched up well.
I'm sorry I couldn't be more help.  I ended up moving on to using other
multivariate analyses like PLSDA and Random Forest because of the seemingly
incompatible analyses.  I wanted to make sure anyone could replicate my
analysis independent of the statistical program.  I poke at it occasionally
but still nothing for the unstructured analysis.  If I ever do I will be
sure to post it.

Wish you the best in you analysis,
Charles


On Wed, Jan 15, 2014 at 1:44 PM, Tony K.-T. <tkamth@gmail.com> wrote:

> Dear Charles,
>
> I have seen your post regarding replicating the results of SAS (Proc
> Mixed) using unstructured covariance matrix using R nlme package (gls).
>  Have you been able to solve this problem?
>
> I am also in the process of doing so on a repeated measures dataset to no
> success (not converging identically, estimates are off), if you can spare
> some thoughts on this it'll be really great.
>
> The model that I am trying to replicate from SAS to R.
>
> PROC MIXED data=Comb method=reml;
>   CLASS FAC1 TIME SUBJECT FAC2;
>   MODEL RESPONSE = BIAS FAC2 FAC1 TIME TIME*FAC1 / ddfm=Residual solution;
>   REPEATED  TIME/ subject=SUBJECT type=un;
> RUN;
>
> Cheers,
>
> --
> Tony Kam-Thong, Dr.-Ing.
> tel.:+41 78 604 5172
> e-mail:tkamth@gmail.com
>



-- 
Charles Determan
Integrated Biosciences PhD Candidate
University of Minnesota

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