[R] Problems with BRugs
R Heberto Ghezzo, Dr
heberto.ghezzo at mcgill.ca
Thu Jun 10 17:54:30 CEST 2010
Hello, I am trying to run some examples from the book of P.Congdon. If I run the following script
# Program 7.2 Bayesian Statistical Modelling - Peter Congdon
#
library(R2WinBUGS)
setwd("c:/temp/R")
mo <- function() {
rho ~ dbeta(1,1)
th ~ dgamma(0.001,0.001)
Y[1] ~ dpois(th)
for (t in 2:14) {Y[t] ~ dpois(mu[t])
for (k in 1:Y[t-1]+1) {B[k,t] ~ dbern(rho)}
B.s[t] <- sum(B[1:Y[t-1]+1,t])-B[1,t]
mu[t] <- B.s[t] +th*(1-rho)}
}
write.model(mo,con="test.bug")
Data <-
list(Y=c(0,1,2,3,1,4,9,18,23,31,20,25,37,45))
Inits <- function() {
list(rho=0.8,th=5)
}
Parameters <- c("rho","mu")
#
p1.sim <- bugs(model.file="test.bug",
Data,
Inits,
n.chains=1,
Parameters,
n.burnin = 1000,
n.iter = 10000,
n.thin=2,
program="WinBUGS",
bugs.directory=Sys.getenv("DirWinBUGS")
)
#
and this works OK given answers similar to the book
But changing library to BRugs, write.model to witeModel and the call to
> #
> p1.sim <- BRugsFit("test.bug",
+ Data,
+ Inits,
+ numChains=1,
+ Parameters,
+ nBurnin = 1000,
+ nIter = 10000,
+ nThin=2
+ )
I get :
model is syntactically correct
data loaded
model compiled
[1] "C:\\Users\\User\\AppData\\Local\\Temp\\RtmphLlekC/inits1.txt"
Initializing chain 1: initial values loaded but this or another chain contain uninitialized variables
model must be initialized before updating
can not calculate deviance for this model
Error in samplesSet(parametersToSave) :
model must be initialized before monitors used
> #
I tried several forms of the Inits and it does not work
Can somebody tell me where is the mistake I am making?
Thanks for any help
Heberto Ghezzo
Montreal
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