unctions can be used in any block and applied to a
mixture of parameters and data (including constants or program
literals).</p>
<p>Random-number-generating functions are restricted to the generated
quantities block; such functions are suffixed with <code>_rng</code>.
Log-probability modifying functions to blocks where the log
probability accumulator is in scope (transformed parameters and
model); such functions are suffixed with <code>_lp</code>.</p>
<p>Density functions defined in the program may be used 