On Sun, Jul 22, 2012 at 9:49 AM, Umut Tabak <u.tabak at tudelft.nl> wrote:
> Dear all, > > I am testing some iterative methods with MATLAB and aside with PETSc > however I have a question which might be answered in the documentation > however I could not find that? > > In MATLAB, at least on recent versions, one can specify a drop tolerance > for the incomplete cholesky preconditioner, I was wondering if the same is > possible with PETSc or not? > You can get an ILUT using MatSuperluSetILUDropTol (-mat_superlu_ilu_droptol) or from Hypre's PILUT (-pc_hypre_pilut_tol). > One more question, is the condition number order 1e+6(estimated with > condest in MATLAB) rather high for an iterative method? With icc, with a > drop tolerance of 1e-3 or 1e-4, as a preconditioner to pcg, I can get > decent iteration numbers to convergence in MATLAB, it is sometimes even > faster than solving the system with the available factorization information > and I was wondering if I can make it faster with some other options in > PETSc or not? > What continuum equations are you solving? What discretization? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120722/69e390f9/attachment.html>
