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

[Rob Clewley]

Hi Tom,

I am not using the latest numpy/scipy versions myself, I have been
using 1.4.1/0.7.0 respectively. There are just a very small number of
test errors with the very latest versions, basically a strange Bus
Error (on Macs at least) for certain symbolic calculations, which I
don't yet understand. Otherwise you should be fine using the latest
ones. Do let me know if you encounter any specific issues on your
platform and setup.

Best,
Rob

On Fri, Jun 3, 2011 at 12:13 PM, Bridgman, William T.
<William.T.Bridgman at nasa.gov> wrote:
> 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/
>
>
>
>
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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