[R] R2WinBUGS with Multivariate Logistic Regression

[Uwe Ligges]

On 17.07.2016 05:33, Christopher Kelvin via R-help wrote:
> Dear R-User,
> I have written a simple code to analyze some data using Bayesian logistic regression via the R2WinBUGS package. The code when run in WinBUGS stops WinBUGS from running it and using the package returns no results also.


I'd suggest to reduce it to a WinBUGS only problem, try OpenBUGS (which 
iw more recent) and if it still fails, ask on the WinBUGS/OpenBUGS 
mailing list. A trap in WinBUGS is not an R related problem.

Best,
Uwe Ligges



>
> I attach herewith, the code and a sample of the dataset.
>
> Any suggestion will be greatly appreciated.
>
> Chris Guure
> Biostatistics Department
>
> University of Ghana
>
>
>
>
> library(R2WinBUGS)
> library(coda)model1<-function(){
> for (i in 1:N) {
> # likelihood function
> ms[i] ~ dbin( p [ i ], N )
> logit(p [ i ] ) <- alpha + bage*age[ i ] + bpam*pam[i ] + bpah*pah[i]
>
> }
> ### prior for intercept
> alpha ~ dnorm(0,0.0001)
>
> # prior for slopes
> bage ~ dnorm(0,0.0001)
> bpam ~ dnorm(0,0.0001)
> bpah ~ dnorm(0,0.0001)
>
>
> # OR for alpha
> or.age<-exp(bage)
> # OR for hbp
> or.pam <- exp(bpam)
> # OR for fdm
> or.pah <- exp(bpah)
>
> }
>
> data=cbind(ms=c(0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0),
> age=c(77, 83, 75, 78, 75, 83, 85, 80, 80, 85, 76, 77, 80, 76, 88, 77, 81, 78, 85, 81),
> pam=c(0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1),
> pah=c(1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0))
> N=20
>
> #### initial values                                                                                             ###
> lineinits <- function(){
> list(alpha=1,bage= 0.05, bpam=0.05, bpah=0.05)
> }
>
> ## CODA output
> lineout1 <- bugs(data, lineinits, c("bage", "alpha","bpam", "bpah", "or.age", "or.pam", "or.pah"), model1,n.iter = 11000, n.burnin = 1000, n.chains = 2, codaPkg = T, DIC = TRUE)
>
>
> ### Posterior summaries
> line.coda <- read.bugs(lineout1)
> summary(line.coda)
>
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