On Monday 19 May 2008, Bill Hart wrote: > You seemed to be getting up to 8% at points there. That's definitely > worth it. I'll be interested to see this evening how it comes out, > though I recommend optimising my combine3 function (which I suppose > should now be combine8), even including it inline rather than have it > in a separate file. > > Of course on the Opteron, SSE should be switched off, since it is > definitely slower by about 5%-10% even with careful optimisation. > > Bill.
Okay, I added SSE2 support again and the timings are pretty good on the C2D: Dimension Old New 10000 x 10000 2.270 1.720 16384 x 16384 9.130 6.760 20000 x 20000 16.110 12.310 32000 x 32000 64.340 50.690 Throwing parallelism in the mix (still lame implementation): Dimension Old New 10000 x 10000 1.470 1.220 16384 x 16384 5.540 4.390 20000 x 20000 11.800 8.580 32000 x 32000 40.040 32.810 Btw. Mike Hansen pointed out on IRC that GAP has a pretty fast implementation of matrix multiplication too: GAP4, Version: 4.4.10 of 02-Oct-2007, x86_64-unknown-linux-gnu-gcc gap> A := RandomMat(10000,10000,GF(2)); <a 10000x10000 matrix over GF2> gap> B := RandomMat(10000,10000,GF(2)); <a 10000x10000 matrix over GF2> gap> C := A*B; <a 10000x10000 matrix over GF2> gap> time; 5951 The unit here is ms so this takes 6 seconds. However, the generation of random matrices takes forever. Mike also pointed out that GAP is twice as fast for the example he tried than the current Sage code (i.e. the code before the improvements discussed in this thread). On sage.math things don't improve as expected: sage: A = random_matrix(GF(2),32000,32000) sage: B = random_matrix(GF(2),32000,32000) sage: time C = A._multiply_strassen(B,cutoff=2^11) CPU times: user 121.69 s, sys: 3.93 s, total: 125.62 s Wall time: 125.62 This was 114.620 before. Martin -- name: Martin Albrecht _pgp: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x8EF0DC99 _www: http://www.informatik.uni-bremen.de/~malb _jab: [EMAIL PROTECTED] --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
