 they
are used — if they do not, the behavior is undefined.</p>
<p>The basis of Stan’s execution is the evaluation of a log probability
function (specifically, a probability density function) for a given
set of (real-valued) parameters. Log probability function can be
constructed by using assignment statements. Statements may be grouped
into sequences and into for-each loops. In addition, Stan allows
local variables to be declared in blocks and also allows an empty
statement consisting only of a semicol