nction
specifying the ODE system as an argument, like PKBugs
<span class="citation">(Lunn et al. <a href="references.html#ref-LunnEtAl:1999" role="doc-biblioref">1999</a>)</span>. Ordinary Stan functions do not allow functions as
arguments.</p>
<p>Second, some of the arguments to the ODE solvers are restricted to
data only expressions. These expressions must not contain variables
other than those declared in the data or transformed data blocks.
Ordinary Stan functions place no restriction on the origin of
v