Have you considered the 'nlme' package, well documented in Pinheiro and Bates (2000) Mixed-Effects Models in S and S-Plus (Springer)?
Hope this helps. Spencer Graves souvik banerjee wrote: > Hi > Is there any way to fit a bivaraite longitudinal mixed model using R. I have > a data set with col names > > resp1 (Y_ij1), resp2 (Y_ij2), timepts (t_ij), unit(i) > > j=1,2,..,m and i=1,2,..n. > > I want to fit the following two models > > Model 1 > > Y_ij1, Y_ij2 | U_i = u_i ~ N(alpha + u_i + beta1*t_ij, Sigma) > U_i ~ iid N(0, sigu^2) > > Sigma = bivariate AR structure > > alpha and beta are vectors of order 2. > > Model 2 > Y_ij, Y_ij2 | U_i = u_i ~ N(alpha + u_i + beta1*t_ij + U_i2*t_ij, Sigma) > > U_i=(U_i1,U_i2) ~ iid N(0, Omega) > > Sigma =bivariate AR structure > > Here alpha and beta are vectors of order 2. > > Moreover can we assume a structure for Omega. > > Any help is greatly appreciated. > Souvik Banerjee > Junior Research Fellow > Dept of Statistics > University of calcutta > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. ______________________________________________ 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.