Re: [ublas] matrix various matrix multiply timing results

From: Toon Knapen (toon.knapen_at_[hidden])
Date: 2005-06-09 05:18:44

Gunter Winkler <guwi17_at_[hidden]> wrote: 
>Am Dienstag, 7. Juni 2005 23:14 schrieb Jack Nguyen:
>Yes, ublas can not (and will not) compete with atlas. You can play with 
>different matrix products and matrix sizes with the attached sample 
>program.
>
>size of metrices - 500x500*500x500
>
>      prod    axpy    opb   block   goto    atlas
>RRR    2.71    1.52    1.73    0.47    0.45    0.12
>RRC    1.17    2.85    1.75    0.47    0.45    0.13
>RCR    6.01    1.57     1.7    0.48    0.45    0.12
>RCC     2.6    2.86    1.72    0.48    0.45    0.13
>CRR     2.6    2.86    1.72    0.47    0.44    0.13
>CRC    1.13    2.84    1.75    0.48    0.45    0.12
>CCR    6.01     1.5    1.71    0.48    0.46    0.11
>CCC     2.7    1.48    1.73    0.47    0.45    0.13
>
>(first column gives storage orientation of X, A and B, other columns 
>present times on my Athlon XP (1466MHz) for X += A*B using different 
>products)
>

I am a bit surprised. I would have expected that [RC]RC would provide
optimal performance because (generally) the prod is calculated by axpy-ing
rows of A with columns of B. Axpy-prod however is slowest on these configs.
BTW: what is 'opb'?