On 13 Nov 2011, at 09:42, c. wrote: > > On 13 Nov 2011, at 00:25, Jordi GutiƩrrez Hermoso wrote: > >> That's a tiny sparse matrix. I'm curious about how the algorithm >> scales. Can you try a couple of orders of magnitude larger? > yes I will.
Hi, This example solves a Laplace equation on a 3d domain with a finite element method, the resulting system is SDP and its condition number scales approximately as (1/N)^2. it's easy to generate larger matrices by increasing N, but unfortunately I can't go much further than what is shown here as I have a 32 bit build of Octave and N=80 is already too large for me. Maybe someone else can generate a larger matrix and place it somewhere for me to download? $ RSB_USER_SET_MEM_HIERARCHY_INFO="L2:4/64/512K,L1:8/64/32K" octave -q >> N = 70; >> pkg load bim >> pp = linspace (0, 1, N); msh = bim3c_mesh_properties (msh3m_structured_mesh >> (pp, pp, pp, 1, 1:6)); >> mat= bim3a_laplacian (msh, 1, 1); >> dn = bim3c_unknowns_on_faces (msh, 1:6); >> in = setdiff (1:columns(msh.p), dn); >> A = mat(in, in); >> f = bim3a_rhs (msh, 1, 1); >> b = f(in); >> P = diag (diag (A)); >> tic (); x = pcg (A, b, 1e-7, 1e3, P); toc () pcg: converged in 154 iterations. the initial residual norm was reduced 1.03076e+07 times. Elapsed time is 9.44405 seconds. >> As = sparsersb (A); >> tic (); xs = pcg (As, b, 1e-7, 1e3, P); toc () pcg: converged in 154 iterations. the initial residual norm was reduced 1.03076e+07 times. Elapsed time is 6.0875 seconds. >> norm (x-xs, inf) ans = 3.2474e-15 >> size (A) ans = 314432 314432 >> nnz (A) ans = 2173280 >> How can I check whether the system is being actually handled in parallel? c. ------------------------------------------------------------------------------ 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