Hi all, I am trying to get a handle on gls (package nlme). I have a toy problem: 3 fixed factors (A, B, C), two levels each, 5 replicates per treatment. The response variable is continuous, normal. I have a correlation matrix of the form:
> mat A B C A 1.00 0.75 0 B 0.75 1.00 0 C 0.00 0.00 1 which is common to all observations. How do I construct the call to gls? I think I need to use correlation=corSymm(), but I do not understand the precise syntax. I have read the relevant parts of Pinheiro and Bates, but they only talk about cases where the corSymm correlation structure is modelled, rather than known. I have also searched the R archives, but no luck. I think it should be of the form gls(response~A*B*C, data=dat, correlation=corSymm(...?)) but I don't understand the arguments to corSymm. Thanks in advance, Simon. Simon Blomberg, PhD Depression & Anxiety Consumer Research Unit Centre for Mental Health Research Australian National University http://www.anu.edu.au/cmhr/ [EMAIL PROTECTED] +61 (2) 6125 3379 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help