Short answer: no.

Long answer:

A `BesselSpace`

may be a bad idea because it has slow convergence. (This is the same situation as using cos/sin for non-periodic functions.) Though perhaps this is worth it in the high-frequency setting. If you wanted to create your own `BesselSpace`

, I’d be happy to walk you through the process.

Otherwise, there used to be a `DiskSpace`

based on a hierarchy of Zernike-like polynomials but the code has gone dormant. I’d be keen to get it working again but have limited time at the moment. @MikaelSlevinsky FastTransforms gives a fast and stable way of expanding functions in this basis which should be incorporated.

For cylinders, one would then need to tensor `DiskSpace`

with `Chebyshev`

. This is almost functioning.

Even then, one needs to solve the resulting system efficiently. Helmholtz has the nice property that it’s radially symmetric so this reduces to 2-dimensional solves involving `BandedBlockBandedMatrix`

, so hopefully that should be efficient. For high frequencies this will break down, but Euan Spence has some nice work on preconditioners for high frequency Helmholtz.