[Algorithms] New research in SH rotations.

[Robin G. <rob...@gm...>]

I received in the mail this morning a print of a paper from a
researcher in "Ambisonics" (the science of multidirectional or
spherical sound field recording and playback), Michael Chapman, who
claims to have new insight into producing rotation matrices for
Spherical Harmonics based on his research into their symmetries:

   http://ambisonics.iem.at/symposium2009/proceedings/ambisym09-chapman-shsymmetries.pdf/at_download/file

Along with this was a reference to a recent 2006 paper on efficient SH
rotations from Pinchon et al where they claim to have improved on
Kautz, Sloan and Snyder's methods not just in generation but in
compact storage as well:

   http://www.math.univ-toulouse.fr/Archive-MIP/publis/files/06.30.pdf

Just in case anyone still cares about efficient rotation of SH functions.

- Robin Green.