Dear all, Some days ago I posted the same message below, but unfortunately with no reply.
So, apologizes for this my re-sending, but I hope there is now someone on-line that can help me.... In using the lme() function from the nlme package, I would like to specify a particular correlation structure for the random effects. For instance, for a 3 by 3 matrix, say, I am interested in assuming a `quasi-diagonal' matrix having zero entries in all but the first column (and the main diagonal, of course) Hence, given the three random effects b1 b2 and b3, I want to assume cov(b2,b3)=0; given four random effects b1,b2,b3,b4 it should be cov(b2,b3)=cov(b4,b2)=cov(b4,b3)=0. For a simple diagonal matrix I specify `random=list(id=pdDiag(~1+x1+x2))', (id is the grouping variable), but I am not able to go on.... Please, could anyone give me any advice? many thanks, vito ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
