Phil Tomson wrote:
> 
> In article <3C9A3A90.C6D96248 / path.berkeley.edu>,
> Joel VanderWerf  <vjoel / PATH.Berkeley.EDU> wrote:
> >
> >A minor comment: you can use Math::exp instead of defining it yourself.
> >
> >I'm glad to see other folks using Ruby for simulation. I'm using it for
> >hybrid systems simulations--hybrid systems are finite state machines
> >with ODE's attached to each state--of vehicle and controllers.
> 
> What's an ODE?

Sorry, ordinary differential equation. The system evolves according to
the equations until some guard condition becomes true (typically a
threshold crossing), and then some discrete state changes happen. When
no more discrete transitions are possible, continuous evolution resumes.

This is a fairly natural setting for multi-agent systems with
logic-based control that are interacting in a physical environment (like
cars on a highway, helicopters, etc.).

> 
> >
> >Any other simulation folks out there?
> >
> 
> I made something called RHDL (Ruby Hardware Description Language) for
> doing hardware simulations (digital logic).  It's still kind of a toy at
> this point.  But I am interested in simulation.

The releasable version of my stuff is also at the toy level, and I have
only released the few pieces that I consider finished. I hope to release
the industrial strength version (fast integration algorithm in C) in a
few weeks. (But I've been hoping that for two months ;-)