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Posterior Density Plots from BRugs

If you're using BRugs to fit your models (which I think has many advantages over using WinBUGS directly), here's how to make a density plot:

If you set the coda option to TRUE, the output object from BRugsFit will be of type mcmc.list. This is a list in which each element is one chain of MCMC samples. Within each chain, you have a matrix with one node in each column. To plot the histogram for both chains for a single node, use code like this:

myfit <- BRugsFit(...,coda=T)
Z13.samples <- unlist(myfit[,'Z[13]',]) # this gets the 'Z[13]' samples from all chains
hist(Z13.samples,freq=F)
lines(density(Z13.samples))