Rjags error message: size mismatch

Question

I am trying to learn Bayesian analysis based on the book "Performing Bayesian Data Analysis: A Tutorial with R, JAGS, and Stan (2015)."

There are examples in this book. So, I am trying to reproduce this example in R. However, in this example I have an error message.

To be specific, these are sample data.

data
   y        s
1  1 Reginald
2  0 Reginald
3  1 Reginald
4  1 Reginald
5  1 Reginald
6  1 Reginald
7  1 Reginald
8  0 Reginald
9  0     Tony
10 0     Tony
11 1     Tony
12 0     Tony
13 0     Tony
14 1     Tony
15 0     Tony

y<-data$y
s<-as.numeric(data$s)
Ntotal=length(y)
Nsubj=length(unique(s))

dataList=list(y=y, s=s, Ntotal=Ntotal, Nsubj=Nsubj)

Also, this is my model.

modelString=" 
model{
  for(i in 1:Ntotal){
    y[i] ~ dbern(theta[s[i]])
  }
  for(s in 1:Nsubj){
    theta[s] ~ dbeta(2,2)
  }
}
"
writeLines(modelString, con="TEMPmodel.txt")

library(rjags)
library(runjags)
jagsModel=jags.model(file="TEMPmodel.txt",data=dataList)

In this case, I got an error message.

Error in jags.model(file = "TEMPmodel.txt", data = dataList) : 
  RUNTIME ERROR:
Cannot insert node into theta[1...2]. Dimension mismatch

I do not know that I made a mistake in this code. Please give me some advice.

Thanks in advance.

Answer 1

@nicola, , s , s , 1:Nsubj. JAGS, theta... 15 2?

:

model{
  for(i in 1:Ntotal){
    y[i] ~ dbern(theta[s[i]])
  }
  for(j in 1:Nsubj){
    theta[j] ~ dbeta(2,2)
  }
}