Thanks for the reply Bob, but it still does not work, you see. I ran this model, just with the main effects and it ran fine.
n=length(bi.bmi) Lgen=2 Lrace=5 Lagegp=13 Lstra=15 Lpsu=2 bi.bmi.model=function(){ # likelihood for(i in 1:n){ bi.bmi[i]~ dbern(p[i]) logit(p[i])<- a0 + a1[agegp[i]]+a2[gen[i]]+a3[race[i]] + g[stra[i]]+ u[psu[i],stra[i]] } # constraints for a1, a2, a3 a1[1]<-0.0 a2[1]<-0.0 a3[1]<-0.0 # priors a0~ dnorm(0.0, 1.0E-4) for(j in 2:Lagegp){a1[j]~ dnorm(0.0, 1.0E-4)} for(j in 2:Lgen){ a2[j]~ dnorm(0.0, 1.0E-4)} for(k in 2:Lrace){ a3[k]~ dnorm(0.0, 1.0E-4)} for(l in 1:Lstra){ g[l]~dunif(0, 100) } for( m in 1:Lpsu){ for(l in 1:Lstra){ u[m,l]~ dnorm(0.0, tau.u) }} tau.u<-pow(sigma.u, -2) sigma.u~ dunif(0.0,100) } library(BRugs) writeModel(bi.bmi.model, con='bi.bmi.model.txt') model.data=list( 'n','Lagegp', 'Lgen', 'Lrace', 'Lstra', 'Lpsu', 'bi.bmi','agegp', 'gen', 'race','stra', 'psu') model.init=function(){ list( sigma.u=runif(1), a0=rnorm(1), a1=c(NA, rep(0,12)), a2=c(NA, rep(0, 1)), a3=c(NA, rep(0, 4)), g=rep(0,Lstra), u=matrix(rep(0, 30), nrow=2) ) } model.parameters=c( 'a0', 'a1', 'a2', 'a3') model.bugs=BRugsFit(modelFile='bi.bmi.model.txt', data=model.data, inits=model.init, numChains=1, para=model.parameters, nBurnin=50, nIter=100) This is just with the main effects, and this does not give me any problems, and I also ran the following model with interaction term between gen and race, and it also ran fine. for (i in 1:n){ bi.bmi[i]~ dbern(p[i]) logit(p[i])<- a0 + a1[agegp[i]]+a2[gen[i]]+a3[race[i]] + a23[gen[i], race[i]] + gam[stra[i]]+ u[psu[i],stra[i]] } # constraints for a2, a3, a12 and a13 a1[1]<-0.0 a2[1]<-0.0 a3[1]<-0.0 a23[1,1]<-0.0 #gen x race for(j in 2:Lrace){ a23[1,j]<-0.0} for(k in 2:Lgen){ a23[k,1]<-0.0} # priors a0~ dnorm(0.0, 1.0E-4) for(i in 2:Lagegp){a1[i]~dnorm(0.0, 1.0E-4)} for(i in 2:Lgen){ a2[i]~ dnorm(0.0, 1.0E-4)} for(i in 2:Lrace){ a3[i]~ dnorm(0.0, 1.0E-4)} for(i in 2:Lgen){ for(j in 2:Lrace){ a23[i,j]~ dnorm(0.0, 1.0E-4) }} for(i in 1:Lstra){ gam[i]~dunif(0, 1000) } for( i in 1:Lpsu){ for(j in 1:Lstra){ u[i,j]~ dnorm(0.0, tau.u) }} tau.u<-pow(sigma.u, -2) sigma.u~ dunif(0.0,100) } So, the error happens only when I try to plug in interaction with the agegp. I still don't know how to correct it. Thanks -- View this message in context: http://n4.nabble.com/BRugs-tp2015395p2016164.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.