error passing model JAGS

Question

I am currently busy with a multiple regression analysis with JAGS toolbox. I'm using runjags, however I still get an error:

Error parsing model file:
syntax error on line 3 near "," 

This how my model looks like:

modelString2 = "
model {
for ( i in 1:Ntotal  ) {
y[i] ~ dnorm( beta[s[i],1] + beta[s[i],2] * x[i,1] + betax[1] * x[i,2] + betax[2] * x[i,3] + betax[3] * x[i,4]), 1/sigma^2 )  
}
for( j in 1 : Nsubj ) {  
beta[j , 1 : 2] ~ dnorm(betamu, R) 
}
for ( k in 1:NxO ){
betax[k] ~ dnorm( 0 , 1/(10)^5 )
}
betamu[1 : 2] ~ dnorm(mean, prec) 
R[1 : 2 , 1 : 2] ~ dwish(Omega, df) 
S<-inverse(R) 
ss[1]<-sqrt(S[1,1]) #var to sd
ss[2]<-sqrt(S[2,2]) #var to sd
ss[3]<-S[1,2]/(ss[1]*ss[2]) #cov to cor 
sigma ~ dunif( 1.0E-3 , 1.0E+3 )
}
"
writeLines(modelString2, con = "multiple_regression.txt")

De error should be in this line:

y[i] ~ dnorm( beta[s[i],1] + beta[s[i],2] * x[i,1] + betax[1] * x[i,2] + betax[2] * x[i,3] + betax[3] * x[i,4]), 1/sigma^2 ) 

However, I have no idea where the error comes from. Somebody who can help me?

Answer 1

It looks as if you have two closing parentheses when you should just have one in that line.

You have:

y[i] ~ dnorm( beta[s[i],1] + beta[s[i],2] * x[i,1] + betax[1] * x[i,2] + betax[2] * x[i,3] + betax[3] * x[i,4]), 1/sigma^2 )

There is a closing parentheses right after x[i,4] and another after 1/sigma^2 for dnorm. The correct placement for it is after 1/sigma^2 so that line should instead be:

y[i] ~ dnorm( beta[s[i],1] + beta[s[i],2] * x[i,1] + betax[1] * x[i,2] + betax[2] * x[i,3] + betax[3] * x[i,4], 1/sigma^2 ).

You could also create a mean (or mu) object instead of putting the linear predictor inside of dnorm, which may reduce the likelihood of this type of error:

for(i in 1:Ntotatl){
y[i] ~ dnorm(mu[i], 1/sigma^2)
mu[i] <- beta[s[i],1] + beta[s[i],2] * x[i,1] + betax[1] * x[i,2] + 
betax[2] * x[i,3] + betax[3] * x[i,4]
}