Contact variational integrators - native ocaml implementation

This is a collection of geometric solvers for initial value problems derived from contact Lagrangians. The provided solvers concern Lagrangians of the form

$$                                         
L(x, \dot{x}, z, t) = \frac12|\dot{x}|^2 + g_1(x)g_2(z) + h(z) + f(t)x
$$

For further information refer to Vermeeren, Bravetti, Seri: Contact Variational Integrators (2019).

Running the integrators on the damped oscillator with and without forcing (see example/damped.ml) produces the following output:

TODO

• Add mli with documentation
• Add implementation with support for g_2(z) as per description
• Figure out how to test