[SciPy-User] Easy way to detect data boundary in integrate.odeint?

[Bridgman, William T.]

Rob,

Thanks for the pointer to this package.

Is there any reports on its robustness in use with the newest scipy &  
numpy?

I'm probably too close to deadline to use with this project, but will  
keep it in mind for future projects.

Thanks,
Tom
On Jun 3, 2011, at 11:48 AM, scipy-user-request at scipy.org wrote:
> Message: 1
> Date: Thu, 2 Jun 2011 15:35:02 -0400
> From: Rob Clewley <rob.clewley at gmail.com>
> Subject: Re: [SciPy-User] Easy way to detect data boundary in
>        integrate.odeint?
> To: SciPy Users List <scipy-user at scipy.org>
> Message-ID: <BANLkTi=hugz-i+FeaUynxW3D3xn=HM68VQ at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> William,
>
>> I'm building streamlines from a 3-D vector array and keep having the
>> problem that if the point I'm propagating reaches the boundary of the
>> data it will sometimes reverse, re-traversing the dataset (really
>> bad), or just repeatedly add points at the boundary (annoying).
>>
>> Is there an easy way to terminate this behavior?
>
> No, this feature is not present in scipy's odeint wrapper.
>
>> I've implemented a version calling odeint in a loop where I check if
>> the output position is still in my data volume with each integration
>> step, but this is notoriously slow.
>
> If speed has become a major issue for you, I recommend my PyDSTool
> package for faster integration with easily set up event detection.
> Both will take place at the level of the C code the package creates
> automatically from your specifications. So it will be very fast. Feel
> free to contact me about setting up if you get stuck with the limited
> documentation online (just google it).
>
> Best,
> Rob
>
> --
> 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

--
Dr. William T."Tom" Bridgman               Scientific Visualization  
Studio
Global Science & Technology, Inc.          NASA/Goddard Space Flight  
Center
Email: William.T.Bridgman at nasa.gov         Code 610.3
Phone: 301-286-1346                        Greenbelt, MD 20771
FAX:   301-286-1634                        http://svs.gsfc.nasa.gov/