JAGS中可能的定向循环

Question

我正在尝试拟合空间状态模型，并且收到此错误消息：

Error in jags.model(file = model.file, data = data, inits = inits, n.chains = n.chains,  : 
  RUNTIME ERROR:
Possible directed cycle involving some or all
of the following nodes:
t[2]
t[3]
t[4]
t[5]
t[6]
t[7]
t[8]
t[9]
v[2]
v[3]
v[4]
v[5]
v[6]
v[7]
v[8]
v[9]

我在这里发现JAGS error - Possible directed cycle involving some or all of the following nodes可能是由于方程t[i]在等式的两边，但我之前在其他空间状态模型中都这样做过，对此我也没有任何问题什么会导致此问题？？？这是模型：

o<-c(22.77619, 19.07782, 22.08817, 16.32168, 32.57081, 10.48027, 15.93440, 27.54557, 33.39933)

cat(file="pop.din","
model {
  t[1] <- n0
  o[1] ~ dlnorm(log(t[1]),tau.obs)
  for (i in 2:9) {
  v[i] <- lambda*t[i] #valor esperado
  t[i] ~ dpois(v[i])  #t valor verdadero
  o[i] ~ dlnorm(log(t[i]),tau.obs)
  }
  lambda ~ dunif(0.1,0.00001)
  tau.obs ~ dgamma(1,10)
  n0 ~ dlnorm(1,0.0001)
}")

pop.din.data<-c("o")

#initial values for the parameters stored as a list
inits<-function()list(lambda=runif(0.01,1),tau.obs=rlnorm(1,1,1),n0=rlnorm(1,1,1))

params<- c("lambda","n0","tau.obs")

ni <- 10000
nt <- 1
nb <- 5000
nc <- 3


library(jagsUI)
j.model   <- jags (model.file = "pop.din", data = pop.din.data,parameters.to.save = params,
                   inits=inits, n.burnin=nb,n.chains = nc,n.iter = ni)


print(j.model)

问候

Answer 1

这是我的问题的解决方案：在这种情况下，空间状态模型将变量的值与其前一次的值相关联，因此应编写过程模型：

cat(file="pop.din","
model{
  #### Data Model
  for(i in 1:n){
    o[i] ~ dlnorm(x[i],tau_obs)
  }

  #### Process Model
  for(i in 2:n){
    v[i]<-lambda*x[i-1] ###not x[i]
    x[i]~dpois(x[i-1])  
  }

  #### Priors
  x[1] ~ dlnorm(x_ic,tau_ic)
  lambda ~dunif(mu,tau_lambda)
  tau_obs ~ dgamma(1,1)
  }")

问候