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 ------------------------------------------------------------------------------ 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
