title: Help with symplectic integrators
body: <p>I'm trying to develop a physics simulation and I want to implement a fourth-order <a href="http://en.wikipedia.org/wiki/Symplectic_integration" rel="noreferrer">symplectic integration</a> method. The problem is that I must be getting the math wrong, since my simulation is not working at all when using the symplectic integrator (as compared to a fourth-order Runge-Kutta integrator that works reasonably well for the simulation). I've been googling this forever and all I can find are scientific articles on the subject. I tried to adapt the method used in the articles, but am having no luck. I want to know if anyone has source code for a simulation that makes use of symplectic integrators, preferably to simulate a gravitational field but any symplectic integrator would do. What language the source is in doesn't matter too much, but I would appreciate a language using C-style syntax. Thanks!</p>