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

[Evgeni Burovski]

On Mon, Mar 2, 2015 at 5:51 PM, Eric Moore <ewm at redtetrahedron.org> wrote:
> 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.


Might be worth to add a line or two about Condon-Shortly phase into
the dosctring as well. Eg, as an example or just with a reference to a
book or software package which does include it.

Evgeni




> 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
>>
>>
>>
>>
>>
>> _______________________________________________
>> SciPy-Dev mailing list
>> SciPy-Dev at scipy.org
>> http://mail.scipy.org/mailman/listinfo/scipy-dev
>>
>
>
> _______________________________________________
> SciPy-Dev mailing list
> SciPy-Dev at scipy.org
> http://mail.scipy.org/mailman/listinfo/scipy-dev
>