I’m attempting to fit the following syntactically-correct logistic model in Stan using HMC via `stan()`

, but am getting an error. The model contains only categorical predictors as well as a categorical response, which I have coded as dummy variables.

```
data {
int<lower = 0> N; // number of samples
int<lower = 0, upper = 1> mislabelled[N]; // vector of mislabelled samples
int<lower = 1, upper = 25> city[N]; // vector of cities
int<lower = 1, upper = 3> source[N]; // vector of sources
int<lower = 1, upper = 4> season[N]; // vector of seasons
int<lower = 1, upper = 12> month[N]; // vector of months
int<lower = 1, upper = 5> status[N]; // vector of species statuses
}
parameters {
real beta0;
vector[24] beta1;
vector[2] beta2;
vector[3] beta3;
vector[11] beta4;
vector[4] beta5;
}
model {
vector[N] eta;
beta0 ~ normal(0, 1);
beta1 ~ normal(0, 1);
beta2 ~ normal(0, 1);
beta3 ~ normal(0, 1);
beta4 ~ normal(0, 1);
beta5 ~ normal(0, 1);
eta = beta0 + beta1[city[1:N]] + beta2[source[1:N]] + beta3[season[1:N]] + beta4[month[1:N]] + beta5[status[1:N]];
mislabelled ~ bernoulli_logit(eta);
}
```

Here is my fake data:

```
library(rstan)
options(mc.cores = parallel::detectCores())
rstan_options(auto_write = TRUE) # only have to compile once unless code is changed
N <- 10
mislabelled <- sample(0:1, N, replace = TRUE)
city <- sample(1:25, N, replace = TRUE)
source <- sample(1:3, N, replace = TRUE)
season <- sample(1:4, N, replace = TRUE)
month <- sample(1:12, N, replace = TRUE)
status <- sample(1:5, N, replace = TRUE)
(fit <- stan("mislabelled.stan", data = list(N = N, mislabelled = mislabelled, city = city, source = source, season = season, month = month, status = status), iter = 2000))
```

The error I am getting is an out-of-range error.

```
Exception: vector[multi] indexing: accessing element out of range. index 3 out of range; expecting index to be between 1 and 2 (in 'model3ee2204da41_mislabelled' at line 28)
```

Line 28 is where the equation for `eta`

is specified.

I’m a bit confused since I don’t have any indices between 1 and 2 as the error seems to suggest.

Any ideas on what’s going on here?