[SciPy-User] Trajectory Integration via scipy.integrate or PyDSTool?

Rob Clewley rob.clewley@gmail....
Mon May 14 12:22:37 CDT 2012


Hi Sara,

I think you should use a tool that's appropriate for the task. With an
hour of work and help on this list or the PyDSTool forum at
http://sourceforge.net/projects/pydstool/forums/forum/472291 you
should be able to get your problem working quickly with PyDSTool. I
expect your problem is easy to solve in PyDSTool, and difficult to do
with odeint.

You can still use scipy's VODE in PyDSTool and you won't need any
fancy installation. Check out the file vode_event_test1.py in the
tests directory. Writing the vector field is simple, but in case you
have specific problems setting up yours then you should send me your
code on list so that I can help. I'd be interested to see what the
equations look like.

It's very simple to define a terminal event, just copy and adapt the
code in the file. You can write a loop so that whenever integration
has stopped because of an event, you reverse the velocity IC and
restart.

-Rob

On Mon, May 14, 2012 at 12:59 PM, Sara Gallian <sara2411@gmail.com> wrote:
> Hi all,
> I'm trying to integrate particle trajectories in a finite domain, and I need to make them "reflect" at the boundaries (i.e. reverse the velocity perpendicular to the plane they collided with). I started by using  scipy.integrate.odeint , but since the integration steps are variable, simply checking the position and reversing the velocity won't work!
> Can anyone suggest the quickest way to obtain this? would Vode be able to handle this, or should I try to learn to use  PyDSTool?
> I'm running pretty late on a deadline, so any suggestion is more than appreciated :)
> Thanks!
> Sara
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> SciPy-User mailing list
> SciPy-User@scipy.org
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-- 
Robert Clewley, Ph.D.
Assistant Professor
Neuroscience Institute and
Department of Mathematics and Statistics
Georgia State University
PO Box 5030
Atlanta, GA 30302, USA

tel: 404-413-6420 fax: 404-413-5446
http://www2.gsu.edu/~matrhc
http://neuroscience.gsu.edu/rclewley.html


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