Hello again, I recompiled petsc using --with-debugging=0 but it doesn't improve the situation much. What's more, when running the program with "-info", I saw "Option SYMMETRIC ignored" and "Option SYMMETRY_ETERNAL ignored". Why are these options ignored? For superlu to specify the symmetric mode with MMD_AT_PLUS_A ordering will significantly shorten the solution time. I didn't find corresponding ordering type in petsc.
Longmin On Thu, Mar 24, 2011 at 3:29 PM, Longmin RAN <longmin.ran at gmail.com> wrote: > Thanks for the tips, Barry. I didn't specify --with-debugging=0 during > the configuration, I think this is the problem. I'll recompile petsc > accordingly to check on this. > > > Longmin > > On Thu, Mar 24, 2011 at 1:30 PM, Barry Smith <bsmith at mcs.anl.gov> wrote: >> >> On Mar 24, 2011, at 5:26 AM, Longmin RAN wrote: >> >>> Hello everyone, >>> >>> >>> I use superlu inside petsc to solve linear systems with symmetrical >>> matrix. The solving time is at least twice longer than using superlu >>> directly. >> >> ? How much of that time is in other parts of the code, not the actual >> superlu solver? Run the PETSc version with -log_summary; the times given in >> the lines >> MatFactorSymbolic, MatFactorNumerical, MatSolve (or some similar names) are >> the amount of time in Superlu. Compare those times to the superlu standalone >> solution time. >> >> ? ?Did you ./configure PETSc with the option --with-debugging=0? >> >> ? Barry >> >> >> >>> Since I'm new with Petsc, I didn't fine-tune much the petsc >>> solver, as I had done when using superlu directly. For example, in >>> superlu there are options like diagonal pivot >>> threshold(superlu_options_t.DiagPivotThresh), symmetric mode >>> (superlu_options_t.SymmetricMode), and column >>> permutation(superlu_options_t.ColPerm). Could anybody inform me about >>> the corresponding options in petsc? Thanks in advance. >>> >>> BTW, I tried the following options: >>> ? ? ? MatSetOption(A, MAT_SYMMETRIC, PETSC_TRUE); >>> ? ? ? MatSetOption(A, MAT_SYMMETRY_ETERNAL, PETSC_TRUE); >>> But it seems that these options weren't enough to reduce the solving >>> time sufficiently. >>> >>> >>> Best regards, >>> >>> - Longmin Ran >> >> >
