[FFmpeg-devel] [PATCH 04/12] Add vector_fmul_matrix to dsputil

[Michael Niedermayer]

On Wed, Oct 21, 2009 at 08:50:37PM +0200, Reimar D?ffinger wrote:
> On Wed, Oct 21, 2009 at 07:22:57PM +0100, M?ns Rullg?rd wrote:
> > Michael Niedermayer <michaelni at gmx.at> writes:
> > 
> > > On Mon, Oct 19, 2009 at 01:00:24AM +0100, M?ns Rullg?rd wrote:
> > >> We are doing len [1 x w]*[w x w] matrix multiplications.
> > >
> > > you can also see it as a single [len x w][w x w] matrix multiplication
> > > and that may also allow faster matrix multiplication algos to be used ...
> > 
> > Do you know a way of multiplying matrixes with fewer operations?
> 
> I'm tempted to say "you don't want to go there". I'd have to read up again,
> but yes, it is possible.

for the generic matrix multiply i agree with you that the algorithms are
probably not worth it but i would have expected that the martrixes we
need to multiply arent random?
That is that they might contain 0, equal elements a*X+b*X=(a+b)*X or
symmetries, but maybe they are random, after all that code is used in
wmapro and thats by ms

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Concerning the gods, I have no means of knowing whether they exist or not
or of what sort they may be, because of the obscurity of the subject, and
the brevity of human life -- Protagoras
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