Hello. I want to specify a diagonal structure for the covariance matrix of random effects in the lme() function.
Here is the call before I specify a diagonal structure: > fit2<-lme(Ln.rgr~I(Ln.nar-log(0.0011)),data=meta.analysis, + random=~1+I(Ln.nar-log(0.0011)|STUDY.CODE,na.action=na.omit) and this works fine. Now, I want to fix the covariance between the between-groups slopes and intercepts to zero. I try do do this using the pdDiag command as follows, but it does not work: > fit2<-lme(Ln.rgr~I(Ln.nar-log(0.0011)),data=meta.analysis, + random=pdDiag(diag(2),~1+I(Ln.nar-log(0.0011))|STUDY.CODE),na.action=na. omit) I get back an error saying that I have zero degrees of freedom. Clearly, the syntax of the command is wrong but I can�t figure out why. The data set (meta.analysis) is not defined as a groupedData object. Any help is appreciated. Bill Shipley Associate Editor, Ecology North American Editor, Annals of Botany D�partement de biologie, Universit� de Sherbrooke, Sherbrooke (Qu�bec) J1K 2R1 CANADA [EMAIL PROTECTED] <http://callisto.si.usherb.ca:8080/bshipley/> http://callisto.si.usherb.ca:8080/bshipley/ [[alternative HTML version deleted]] ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
