Re: gsl_quaternion proposition

[linas at austin dot ibm dot com (Linas Vepstas)]

I demand that Robert G. Brown are belonging when Wed, May 10, 2006 at 10:47:01AM -0400:
> On Wed, 10 May 2006, picca@synchrotron-soleil.fr wrote:
> 
> >Hello
> >
> >I attached here a proposition for a gsl_quaternion base on the gsl_complex.

The code looks very professionally designed and well-pt-together.
However, it does nothing more than to define a type and some basic
operations on it (add, multiple, conjugate, etc).

What is the intent of this? Are you thinking of creating some 
gsl_sf_* routines to accept this type? What's the grand vision?

Surely the isomorphism of the quaternions to the algebra of rotations 
for 3D space SO(3)=SU(2)/Z2 is too shallow a justification for 
introducing a new type?

> Interesting idea.  Are you thinking of adding support for generalized
> geometric (division) algebras (clifford algebras) of arbitrary grade or
> just quaternions?

The other possible way to generalize is to su(n) and other Lie algebrs,
but I don't see the point.

--linas