[vorbis-dev] Dot Product

[Gregory Maxwell]

On Thu, Feb 19, 2004 at 10:43:30AM -0500, Patrick Joseph Curran wrote:
> On Wed, 18 Feb 2004, Sebastian Gesemann wrote:
> > Yes, this is correct. Actually there're 3 products:
> > 1) cross product: (defined in R^3)
> >    vector X vector --> vector
> > 2) dot product:
> >    vector X vector --> vector
> > 3) scalar product:
> >    vector X vector --> scalar
> >
> > the dot-product can be computed in matlab using the operator ".*"
> > the vectors are component-wise multiplicated as you did it.
> 
> As others have mentioned, your dot product doesn't really fit with the
> math definitions of the standard dot product.
> [see:http://en.wikipedia.org/wiki/Inner_product_space] But it seems to be
> an invention of vorbis.  Well I have never seen it before.  I vote for a
> name change, for clarity's sake.  Also the cross product can be done in
> R^n, n>1, if you really need to do it.

Ah. I think I probably introduced the bad terminology into the community
here.. Octave/matlab denotes element wise operation on matrixes with
".operator".. so elementwise multiplication is ".*" .. 'dot-product' ...
the similarity in computation to an actual dot-product caused me to use
that term to describe it... it seems my bad information infected others.

What is wanted in vorbis is element wise multiplication.. which is the
only thing that makes sense in the codec there..

<p><p><p>--- >8 ----
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