Dear Dr Skaug and R users, just discovered glmm.admb in R, and it seems a very useful tool. However, I ran into a problem when I compare two models:
m1<-glmm.admb(survival~light*species*damage, random=~1, group="table", data=bm, family="binomial", link="logit") m1.1<-glmm.admb(survival~(light+species+damage)^2, random=~1, group="table", data=bm, family="binomial", link="logit") anova(m1, m1.1) I get the following output with the warning Analysis of Variance Table Model 1: survival ~ light * species * damage Model 2: survival ~ (light + damage + species)^2 NoPar LogLik Df -2logQ P.value 1 9.000 -103.307 2 9.000 -103.781 0 -0.948 Warning message: NaNs produced in: pchisq(q, df, lower.tail, log.p) The warning is generated because the df=0. This appears to be because the number of parameters is being incorrectly calculated (they should be 9 and 8 respectively). I had a look at the function call in R, and the problem appears to be because npar is obtained from the file nbmm.par on line 140 of the function out$npar <- as.numeric(scan("nbmm.par", what = "", quiet = TRUE)[6]) which doesn't appear to change between calculations (the file seems to hvae been created the first time I ran glmm.admb, and not to have been modified since). Replacing this line with the following out$npar<-p+m seemed to work ok. Is this a legitimate solution? I noticed that this isn't necessary for when I run the example for anova.glmm.admb (although this uses a different family). This seems to overwrite the nbmm.par file. Couldn't work out where this happens though, and take it that this occurs during the call to the ADMB program. Any thoughts? Many thanks Robert Below is the version information for R platform i386-pc-mingw32 arch i386 os mingw32 system i386, mingw32 status major 2 minor 2.0 year 2005 month 10 day 06 svn rev 35749 language R ADMB version Package: glmmADMB Version: 0.2 License: GPL Packaged: Thu Dec 1 07:02:40 2005; andersn Built: R 2.2.0; ; 2005-12-01 07:13:48; unix -- Robert Bagchi Animal & Plant Science Alfred Denny Building University of Sheffield Western Bank Sheffield S10 2TN UK t: +44 (0)114 2220062 e: [EMAIL PROTECTED] [EMAIL PROTECTED] http://www.shef.ac.uk/aps/apsrtp/bagchi-r ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html