[MPlayer-dev-eng] [OT] C-code Optimiation Contest

[Michael Niedermayer]

Hi

On Tuesday 15 July 2003 02:12, Arpi wrote:
> Hi,
>
> > if you like to have some fun, try optimizing the attached simple matrix
> > multiply and post your results.
> >
> > The Rules:
> > 1. you may only modify multiply_d.[ch] (NUM should stay 512 though)
> > 2. you may change compiler and optims in Makefile
> > 3. precision must stay the same
> > 4. to compare, you should compile the orginal code:
> >     make && copy matrix matrix.org && (./matrix.org >res.org)
> > 5. then later you can compare results via:
> >    make && (./matrix >res.txt) && diff -q res.org res.txt
> >
> > Have fun!
> >
> > Btw. current results by me is 738% of original speed, arpis results are
> > even better, as he included my tips in his alredy optimized code =))))
>
> ok here is my (ok, our:)) contribution:
>
> to get best results (19.628 faster than original) set DIM to 516 in the .h
hmm, only ~20x faster ...
i get ~1000x faster (see attached) :)))

[...]
-- 
Michael
level[i]= get_vlc(); i+=get_vlc();		(violates patent EP0266049)
median(mv[y-1][x], mv[y][x-1], mv[y+1][x+1]);	(violates patent #5,905,535)
buf[i]= qp - buf[i-1];				(violates patent #?)
for more examples, see http://mplayerhq.hu/~michael/patent.html
stop it, see http://petition.eurolinux.org & http://petition.ffii.org/eubsa/en
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