Numerical simulation of systems of differential equations is
made by the `ode` primitive. Many solvers are available,
mostly from `odepack`, for solving stiff or non-stiff systems.
Implicit systems can be solved by `dassl`. It is also
possible to solve systems with stopping time: integration
is performed until the state is crossing a given surface.
See `ode` and `dassrt` commands. There is a number
of optional arguments available for solving ode's (tolerance
parameters, jacobian, order of approximation, time steps etc).
For ode solvers, these parameters are set by the global
variable `%ODEOPTIONS`.

Minimizing non linear functions is done the `optim` function.
Several algorithms (including non differentiable optimization)
are available. Codes are from INRIA's `modulopt` library.
Enter `help optim` for more a more detailed description.