,
<code>ordered</code> for ordered vectors of scalars and
<code>positive_ordered</code> for vectors of positive ordered
scalars. There are specialized matrix data types <code>corr_matrix</code>
and <code>cov_matrix</code> for correlation matrices (symmetric, positive
definite, unit diagonal) and covariance matrices (symmetric, positive
definite). The type <code>cholesky_factor_cov</code> is for Cholesky
factors of covariance matrices (lower triangular, positive diagonal,
product with own transpose is a cova