[SciPy-dev] Hankel transform

Stéfan van der Walt stefan@sun.ac...
Mon Dec 15 03:07:54 CST 2008


Hi all,

Could someone familiar with the Hankel transform please comment on Tom's offer?

Thanks
Stéfan

2008/12/3 Tom Grydeland <tom.grydeland@gmail.com>:
> Hi developers,
>
> When I recently needed a Hankel transform I was unable to find one in
> Scipy.  I found one in MATLAB though[1], written by Prof. Brian
> Borchers at New Mexico Tech. The code is based on a previous FORTRAN
> implementation by W. L. Anderson [2], and the MATLAB code is not
> marked with any copyright statements.  Hankel transforms of the first
> and second order can be computed through digital filtering.
>
> I have rewritten the code in Python/numpy, complete with tests and
> acknowledgements of the origins, and my employer has agreed that I can
> donate the code to Scipy.  I believe this should be of interest.
> Hankel transforms arise often in acoustics and other systems with
> cylinder symmetry.  If you want it, I would like a suggestion where it
> belongs (with other integral transforms, probably) and how I should
> shape the tests to make them suitable for inclusion.
>
> The tests I currently have use Hankel transforms of five different
> functions with known analytical transforms and compares the
> transformed values to the numerically evaluated analytical
> expressions.  Currently plots are generated, but for automated testing
> I suppose something else would be better.  Pointing me at an example
> is sufficient.
>
> [1] http://infohost.nmt.edu/~borchers/hankel.html
> [2] Anderson, W. L., 1979, Computer Program Numerical Integration of
> Related Hankel Transforms of Orders 0 and 1 by Adaptive Digital
> Filtering. Geophysics, 44(7):1287-1305.
>
> Best regards,
>
> --
> Tom Grydeland


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