[R] animal models and lme

[Douglas Bates]

<iwhite at staffmail.ed.ac.uk> writes:

> Not convinced that responses so far have addressed the problem. The
> model is
> 
> y = mu + U + e
> 
> where e is a vector of independendent errors with variance ve, and U
> is a vector of random effects with covariance matrix va*A, where A is a
> known matrix (which we can assume is a correlation matrix). If we know the
> ratio (va/ve), this reduces to a GLS problem, but not otherwise. Usually
> we have to estimate both ve and va.

Sorry to say that I don't think lme will handle that problem gracefully.