Hi All I havent seen that lme or lmer allows to specify certain constraints (although I heard one could program ones own covariance structure). Specific constraints, including one on the residual variance can be specified in sas proc mixed. In my model I want to fix the residual variance to the known value of 0. If anyone having an idea about that, I would appreciate letting me know.
Thanks Toby ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.