Peter Bruin on Thu, 08 Oct 2015 17:51:17 +0200 |
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Re: Faster digits and fromdigits in base 2^k, and FlxqM_mul_Kronecker |
Hi Bill, > On Thu, Oct 08, 2015 at 02:53:30PM +0200, Peter Bruin wrote: >> Bonjour, >> >> My motivation for this was mostly to speed up multiplication of matrices >> over non-prime finite fields of small characteristic (FlxqM). I am >> attaching a second patch (FlxqM_mul_Kronecker.patch) that enhances >> Kronecker multiplication for FlxqM to use the above functions for >> packing into and unpacking from integer matrices in cases where it >> allows us to pack the entries in fewer words per entry than the >> (half-)word-aligned packing that is used now. > > Hello Peter, > > Thanks for your patch! > > Is that method applicable to ZX_mul and Flx_mul ? > (What about ZX_eval2BILspec/Z_mod2BIL_ZX (and > Flx_mulspec_mulii_inflate/Z_mod2BIL_Flx)) ? In principle it is, but it is harder to make it pay off because the overhead remains non-negligible. I spent some time trying to apply this method to Flx_mul; so far I haven't managed to get a systematic speed-up over the existing code, but I am still optimistic that some improvement may be possible. As for ZX_mul, I haven't looked at that yet. Cheers, Peter