I demand that [EMAIL PROTECTED] are belonging when Thu, May 11, 2006 at 02:27:29PM +0200: > On Wed, 10 May 2006 12:03:20 -0500 > [EMAIL PROTECTED] (Linas Vepstas) wrote: > > > What is the intent of this? Are you thinking of creating some > > gsl_sf_* routines to accept this type? What's the grand vision? > > For me the intend is to use quaternions to compute rotations in the 3D > space.
OK. > It is more accurate than matrix multiplication. !! I'm a little surprised by this statement. The round-off errors from working with a 2x2 matrix directly, versus decomposing it via the 2x23 Paul matrices (quaternions) would seem to be nearly the same. > > The other possible way to generalize is to su(n) and other Lie algebrs, > > but I don't see the point. > > Maybe but I do not have the competences to do the generalization. > With your help why not ? Many reasons not to do it: -- presumably, there are already algebra packages that do this. -- this is breaking new ground for GSL; there's no precedent. -- I personally have no grand vision for what to do with this. I can imagine useful tools: maybe something that automatcally gave you the different representations. Something that automatically allowed you to work in homogenous spaces (aka the Wigner-Seitz cells for general Lie groups). Something that atomatically computed Anosov flows/horocycle flows. Generalizations of hypergeometric functions. Generalizations of 3-j and 6-j symbols. I dunno. This is all obscure, narrow-interest stuff. I don't know what others would find useful. --linas
