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Support Bessel polynomials?

Open MikaelSlevinsky opened this issue 8 years ago • 7 comments

And if so, what kind of fast transform is applicable? I've heard they're related to Jacobi polynomials with negative parameters, but they might transform nicely to Taylor polynomials.

MikaelSlevinsky avatar Sep 12 '17 21:09 MikaelSlevinsky

Do you want the Bessel-Fourier transform?

ajt60gaibb avatar Sep 12 '17 22:09 ajt60gaibb

Sure!

MikaelSlevinsky avatar Sep 13 '17 12:09 MikaelSlevinsky

We discussed last year that the connection coefficients matrix between Bessel polynomials of different parameters is diagonally scaled Toeplitz-dot-Hankel, but decided in the end not to put it in the Fast Polynomials Transforms paper. Not sure if that Hankel matrix is positive definite or not.

See prop 5.1 of https://cmup.fc.up.pt/main/sites/default/files/publications/ConnectionCoefficients_CMUP_3.pdf https://cmup.fc.up.pt/main/sites/default/files/publications/ConnectionCoefficients_CMUP_3.pdf

Marcus

On 13 Sep 2017, at 20:41, Richard Mikael Slevinsky [email protected] wrote:

Sure!

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marcusdavidwebb avatar Sep 15 '17 03:09 marcusdavidwebb

Yeah it looks like the reverse Bessel polynomials are related to generalized Laguerre polynomials whose orders are related to the degree... not sure which approximation space they're designed for.

MikaelSlevinsky avatar Sep 18 '17 20:09 MikaelSlevinsky

there is this for discrete Hankel https://www.gnu.org/software/gsl/doc/html/dht.html but it would be great to have a Bessel-Fourier as part of FastTransforms.jl

AshtonSBradley avatar Jun 08 '18 23:06 AshtonSBradley

Back in September 2017, I was thinking about translating the transforms that I wrote in MATLAB:
https://github.com/ajt60gaibb/FastAsyTransforms The algorithms in the GNU package are not optimal complexity and could be improved.

ajt60gaibb avatar Jun 10 '18 14:06 ajt60gaibb

All contributions welcome! No reasonable pull request left behind.

Cheers,

Mikael

On Jun 10, 2018, at 9:25 AM, Alex Townsend <[email protected]mailto:[email protected]> wrote:

Back in September 2017, I was thinking about translating the transforms that I wrote in MATLAB: https://github.com/ajt60gaibb/FastAsyTransforms The algorithms in the GNU package are not optimal complexity and could be improved.

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MikaelSlevinsky avatar Jun 10 '18 19:06 MikaelSlevinsky