I have two variables (one data, one parameter) which should be upper or lower triangular matrices, but they aren’t Cholesky factors of anything. Is it ok to use the `cholesky_factor_cov`

data type for this?

*edit* if so, can a prior be set using `to_vector`

, e.g.

```
cholesky_factor_cov[5] tri;
to_vector(tri) ~ beta(a, b);
```

or would one need to loop through each element?

I was worried about declaring a `matrix`

parameter and the other triangle being unconstrained for estimation (and generally slowing things down).

I searched the forum and found only hints, but I wanted to confirm from an implementation perspective this works.