Hi, I am new to this list. I have a question regarding including both spatial and temporal random factors in lmer. These two are not nested, and an example of model I try to fit is
model1<-lmer(Richness~Y+Canopy+Veg_cm+Treatment+(1|Site/Block/Plot)+(1|Year), family=poisson, REML=FALSE), where richness = integer Y & Treatment = factor Canopy & Veg_cm = numerical, continous Site/Block/Plot= factor Year = integer I get the following warning message: Warning messages: 1: In mer_finalize(ans) : Cholmod warning 'not positive definite' at file:../Cholesky/t_cholmod_rowfac.c, line 432 2: In mer_finalize(ans) : singular convergence (7) Is this due to the nature of my fixed/random factors or the way I put up the random factors? In lme I could include a component for autocorrelation, ex:cor=corAR1(form=~Year|Site/Block/ID). Does the equivalent exist for lmer? I will be very happy if someone can help me! -- Thanks a lot Marte ______________________________________________ R-help@r-project.org 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.
