Re: [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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