[SciPy-Dev] Spherical Harmonics and Condon-Shortley phase

[Eric Moore]

An explicit formula for what is calculate is given in the docs:
http://docs.scipy.org/doc/scipy-dev/reference/generated/scipy.special.sph_harm.html#scipy.special.sph_harm.
But the short answer is that it does not include the Condon-Shortly phase.
Probably still worth comparing what it provides to what you expect if you
haven't already.

This particular function was made into a ufunc last summer (instead of
being implemented as a python function).   I'd try to use a current Scipy
if you will need to call this a lot, its likely to me substantially faster.

Eric

On Thu, Feb 26, 2015 at 9:33 AM, Freddy Rietdijk <freddyrietdijk at fridh.nl>
wrote:

> Hi,
>
> I'm working with auralization and Ambisonics, and the directivity patterns
> that are used with Ambisonics are spherical harmonics. Scipy has an
> implementation, scipy.special.sph_harm. Several definitions exist however
> for spherical harmonics, and the documentation does not specify which is
> implemented.
>
> A common definition that is used in quantum-mechanics includes the
> Condon-Shortley phase, which is a (-1)**m factor.
>
> http://en.wikipedia.org/wiki/Spherical_harmonics#Condon.E2.80.93Shortley_phase
>
> For my purpose, Ambisonics, I need spherical harmonics without this factor.
> I found the code, which uses external functions, quite difficult to read.
> I did see `(-1)**mp` but I'm not sure now whether this really is the CS
> phase or not.
>
> Who knows which definition is used in `sph_harm`?
>
> Frederik
>
>
>
>
>
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>
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