大家好,新人写ARSV模型,不过遇到问题不能运行,显示 unable to generate initial value for node <theta[1]> of type UpdaterAMblock.UpdaterHetro, 实在是不知道什么原因了,model syntex is correct, load data 也没问题,大家能帮我找找原因么?万分感谢,模型代码如下
model{
for (i in 1:N) {
Yisigma2 <- 1/exp(theta);
Y~ dnorm(0,Yisigma2);
}
###########################
phistar ~ dbeta(20,1.5);
phi <- 2*phistar - 1;
psistar ~ dbeta(20,1.5);
psi <- 2*psistar - 1;
mu ~ dnorm(0,0.1);
beta <- exp(mu/2);
itau2 ~ dgamma(2.5,0.025);
tau <- sqrt(1/itau2);
###########################
theta0 ~ dnorm(mu,itau2);
thetamean[1] <- mu + phi*(theta0-mu);
theta[1] ~ dnorm(thetamean[1],itau2);
thetamean[2] <- mu + phi*(theta0-mu) + psi*(theta[1]-mu);
theta[2] ~ dnorm(thetamean[2],itau2);
for (i in 3:N) {
thetamean <- mu + phi*(theta[i-1]-mu) + psi*(theta[i-2]-mu);
theta ~ dnorm(thetamean,itau2);
}
}