Dear sage-support team,
Michael wrote:
> > When i take a 4x4 matrix over GF(7) with n=1000001, test function 1
> > needs 92.50 s CPU time, but test function 2 only needs 1.49 s CPU
> > time!
> > Hence, in that case, MeatAxe (actually a very old version!!) appears
> > to be faster than Sage built with Atlas, by a factor of >60!
<snip>
> Sage has so far only optimized the large case, but 2.8.6 (out in a day or
> so) should contain a patch that improves the small case also.
In fact, the new version is faster -- but not much. 10^6
multiplications of some 4x4 matrix over GF(7) took about 59 seconds of
CPU time using Sage matrices (disclaimer: It is not clear to me if
Sage 2.8.6 has found my ATLAS BLAS).
Meanwhile i learned how to turn MeatAxe matrices into an extension
type 'MTX' for Sage. Apparently there is some overhead in my
implementation (and some functionality is still missing), but 10^6
multiplications of the same 4x4 matrix over GF(7) only took 4.3
seconds of CPU time using the MTX extension type.
I used a MeatAxe with copyright dating from 1994, for the simple
reason that the programs of my boss are based on it. I consider it as
an "oddity" that it uses multiplication tables that are stored in a
file. I don't know if this has changed in new MeatAxe versions.
Cheers
Simon
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