Dear R and lme4 users- I am trying to fit a mixed-effects model, with the glmer function in lme4, to right-skewed, zero-inflated, non-normal data representing understory grass and forb biomass (continuous) as a function of tree density (indicated by leaf-area). Thus, I have tried to specify a Gamma distribution with a log-link function but consistently receive an error as follows:
> total=glmer(total~gla4+(1|plot)+(1|year/month),data=veg,family=Gamma(link=log)) > summary(total) Error in asMethod(object) : matrix is not symmetric [1,2] I have also tried fitting glmm's with lme4 and glmer to other Gamma-distributed data but receive the same error. Has anyone had similar problems and found any solutions? Thank you for your input. Best regards, ___________________________________ Matt Giovanni, Ph.D. NSERC Visiting Research Fellow Canadian Wildlife Service 2365 Albert St., Room 300 Regina, SK S4P 4K1 306-780-6121 work 402-617-3764 mobile http://sites.google.com/site/matthewgiovanni/ ______________________________________________ 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.
