On Sun, Nov 13, 2011 at 10:20 PM, Alexander Barth <barth.alexan...@gmail.com> wrote: > On Sun, Nov 13, 2011 at 12:41 AM, Michele Martone > <michele.mart...@ipp.mpg.de> wrote: >> On 20111112@18:25, Jordi Gutiérrez Hermoso wrote: >>> On 12 November 2011 18:18, Carlo de Falco <carlo.defa...@gmail.com> wrote: >>> > On 12 Nov 2011, at 16:04, c. wrote: >>> >> On 12 Nov 2011, at 12:17, Alexander Barth wrote: >>> > .... >>> > It looks like it's working: >>> > >>> >>> n = 1000; >>> >>> A = 15 * eye (n) + sprandn (n, n, .2); >>> >>> b = ones (n, 1); >>> >>> P = diag (diag (A)); >>> >>> tic, [x, flag] = gmres (A, b, [], 1e-7, n, P); toc >>> > Elapsed time is 1.73299 seconds. >>> >>> As = sparsersb (A); >>> >>> tic, [x, flag] = gmres (As, b, [], 1e-7, n, P); toc >>> > Elapsed time is 1.40307 seconds. >>> > >>> > the speed-up is nothing to write home about though but, still, >>> > it's a really nice package and already usable, >>> > so Michele keep up with the good work :) >>> >>> That's a tiny sparse matrix. I'm curious about how the algorithm >>> scales. Can you try a couple of orders of magnitude larger? >>> >>> Also, what version of Octave is that? Are you working on dev or stable? >> Hahahaha :) >> Yes Jordi is right: you should try much large matrices, possibly with >> tens of elements per row. >> See the articles on http://claudius.ce.uniroma2.it/~martone/ as soon as >> the webserver is back to life. >> I have yet to document much of librsb: there are different tuning >> parameters involved in librsb's operation. >> >> But generally, with smaller matrices (e.g.: as a rule of thumb, ones >> fitting in the L2 cache) it's not even said that operation was really >> parallel (it depends on the matrix partitioning; maybe this could be >> interesting to "visualize" in some way...; if the "recursive >> partitioning" was not applied at all, operation was serial). >> >> > > Dear Michele, > > I would like to try the suggestion of Filippone, but I sumbled upon a > a segmentation fault for the following matrix multiplication: > > load test.mat % http://modb.oce.ulg.ac.be/mediawiki/upload/Alex/test.matbut > [i,j,s]=find(A); > A2 = sparsersb(i,j,s); > [i,j,s]=find(extx); > extx2 = sparsersb(i,j,s); > extx2*A2; > > panic: Segmentation fault -- stopping myself... > attempting to save variables to `octave-core'... > save to `octave-core' complete > Segmentation fault > > Any help would be appreciated, > Cheers, > Alex >
somehow, the link to the test data was modified. The correct link is http://modb.oce.ulg.ac.be/mediawiki/upload/Alex/test.mat cheers, Alex ------------------------------------------------------------------------------ RSA(R) Conference 2012 Save $700 by Nov 18 Register now http://p.sf.net/sfu/rsa-sfdev2dev1 _______________________________________________ Octave-dev mailing list Octave-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/octave-dev
