On 02/03/16 22:28, Justin Chang wrote: ...
> Down solver (pre-smoother) on level 3 > > KSP Object: (solver_fieldsplit_1_mg_levels_3_) > linear system matrix = precond matrix: ... > Mat Object: 1 MPI processes > > type: seqaij > > rows=52147, cols=52147 > > total: nonzeros=38604909, allocated nonzeros=38604909 > > total number of mallocs used during MatSetValues calls =2 > > not using I-node routines > > Down solver (pre-smoother) on level 4 > > KSP Object: (solver_fieldsplit_1_mg_levels_4_) > linear system matrix followed by preconditioner matrix: > > Mat Object: (solver_fieldsplit_1_) ... > > Mat Object: 1 MPI processes > > type: seqaij > > rows=384000, cols=384000 > > total: nonzeros=3416452, allocated nonzeros=3416452 This looks pretty suspicious to me. The original matrix on the finest level has 3.8e5 rows and ~3.4e6 nonzeros. The next level up, the coarsening produces 5.2e4 rows, but 38e6 nonzeros. FWIW, although Justin's PETSc is from Oct 2015, I get the same behaviour with: ad5697c (Master as of 1st March). If I compare with the coarse operators that ML produces on the same problem: The original matrix has, again: Mat Object: 1 MPI processes type: seqaij rows=384000, cols=384000 total: nonzeros=3416452, allocated nonzeros=3416452 total number of mallocs used during MatSetValues calls=0 not using I-node routines While the next finest level has: Mat Object: 1 MPI processes type: seqaij rows=65258, cols=65258 total: nonzeros=1318400, allocated nonzeros=1318400 total number of mallocs used during MatSetValues calls=0 not using I-node routines So we have 6.5e4 rows and 1.3e6 nonzeros, which seems more plausible. Cheers, Lawrence
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