Trouble with multiple definitions of node

Question

The model is syntactically correct, I loaded the data but when I compile, I get this error : "multiple definitions of node z". I don't know how to solve it

 model{

    ...
    for(i in 1:r){
      for(j in 1:r){
        z[i,j] <- ((step(x[i,j]-0)*1) + (1-step(x[i,j]-0)*(-1)))/2
      }
    }

    # (zij +1)/2
    for (j in 1:r) {
        for (i in 1:r) {
            z[i, j] ~ dbern(p[j])
        }
    }
    ...

}

Some help would be appreciated.

Answer 1

You have defined multiple parts if z twice. BUGS does not allow you to overwrite z (or any other node) in the same model, i.e. you can only write one of z~ or z<- once.