Hi!

I’m currently running into an issue with model specification as part of an ODE system I’m trying to solve- I’m doing the following:

```
transformed parameters {
real params[nStudies, 9];
real y0[nStudies, 3];
for(i in 1:nStudies){
params[i, 1] = epsilon;
params[i, 2] = muMF_0;
params[i, 3] = muW;
params[i, 4] = foi[i];
params[i, 5] = muMF_1_max[i];
params[i, 6] = rho[i];
params[i, 7] = beta_1_max[i];
params[i, 8] = lambda[i];
params[i, 9] = treatment_time;
y0[i, 1] = fertile_worms_equilibrium(foi[i], muW);
y0[i, 2] = 0;
y0[i, 3] = mf_equilibrium(epsilon, y0[1, i], muMF_0);
}
}
model{
real y_hat[nStudies, K, 3];
for(i in 1:nStudies){
y_hat[i] = integrate_ode_rk45(LoaModel, to_array_1d(y0[i]), t0, time, to_array_1d(params[i]), x_r, x_i);
}
- some other code underneath-
}
```

And I’m getting this error message:

`stan second argument to integrate_ode_rk45 must have type real[] for intial system state; found type=real[,]. fifth argument to integrate_ode_rk45 must have type real[] for parameters; found type=real[,].`

Does anyone have any idea what’s going on? I was expecting `to_array_1d`

to give me `real[]`

but evidently not! Any and all help would be massively appreciated!