Hi there! I am trying to estimate the stan model below in Rstan:

```
data {
int<lower=0> N; // Number of patents
int<lower=0> K; // Number of firms
int<lower=0> P; // Number of covariates
int<lower=1,upper=K> firm[N]; // Firm index for each patent
matrix[K, P] W; // Firm-specific covariates
vector[N] c; // Number of citations
}
parameters {
vector[K] mu_k;
vector<lower=0>[K] sigma_yk;
vector[K] t_k;
vector[N] y;
real mu;
real mu_t;
vector[P] beta_mu;
vector<lower=0>[2] theta;
cholesky_factor_corr[2] Omega;
real<lower=0> sigma_c;
}
model {
vector[N] p_ik;
// Priors
mu ~ normal(0, 1000);
mu_t ~ normal(0, 1000);
beta_mu ~ normal(0, 1000);
theta ~ cauchy(0, 10);
Omega ~ lkj_corr_cholesky(3);
sigma_yk ~ uniform(0, 1000000);
sigma_c ~ uniform(0, 1000000);
// Model equations
for (k in 1:K) {
vector[2] mu_tk = [mu + W[k] * beta_mu, mu_t]';
matrix[2, 2] V = quad_form_diag(Omega, theta);
[mu_k[k], t_k[k]]' ~ multi_normal(mu_tk, V);
}
for (i in 1:N) {
int k = firm[i];
y[i] ~ normal(mu_k[k], sigma_yk[k]);
p_ik[i] = y[i] >= t_k[k] ? 1.0 : 0.0;
target += normal_lpdf(c[i] | y[i], sigma_c) * p_ik[i];
}
}
```

And am getting the following error:

```
[1] "Error in sampler$call_sampler(args_list[[i]]) : Initialization failed."
error occurred during calling the sampler; sampling not done
```

Any ideas as to why this may be happening? I am happy to provide more information as needed, but I’m guessing there is something wrong with how I’ve specified the model here. Given the vagueness of the error though, it’s been hard to figure out exactly what is wrong. Thank you in advance!