Dear all, I'm trying to solve a stokes flow with constant viscosity but with non-zero divergence prescribed in the rhs.
I have a matrix created from DMDA (mDa) of 4 dofs: vx, vy, vz and p respectively. I have another DMDA (mDaP) of same size but of 1 dof corresponding to only p. I have assigned the null space for constant pressure inside the code. I have assigned two nullspace basis: One corresponding to vector created from mDa that is assigned to outer ksp. Second corresponding to vector created from mDaP that is assigned to a ksp obtained from the fieldsplit corresponding to the schur complement. Now when running the code, the solver converges for up to certain size, e.g. 92X110 X 92 (the results for this convegent case with -ksp_view is given at the end of the emal. But when I double the size of the grid in each dimension, it gives me a run-time error. The options I've used are of the kind: -pc_type fieldsplit -pc_fieldsplit_type schur -pc_fieldsplit_dm_splits 0 -pc_fieldsplit_0_fields 0,1,2 -pc_fieldsplit_1_fields 3 -fieldsplit_0_pc_type hypre -fieldsplit_0_ksp_converged_reason -fieldsplit_1_ksp_converged_reason -ksp_converged_reason -ksp_view Here are: 1. Error message when using hypre for fieldsplit_0 2. Error message when using gamg for fieldsplit_0 3. -ksp_view of the working case using hypre for filedsplit_0 I get following error when I use hypre : 1. ****************************************************************************************************** [5]PETSC ERROR: --------------------- Error Message ------------------------------------ [5]PETSC ERROR: Signal received! [5]PETSC ERROR: ------------------------------------------------------------------------ [5]PETSC ERROR: Petsc Release Version 3.4.3, Oct, 15, 2013 [5]PETSC ERROR: See docs/changes/index.html for recent updates. [5]PETSC ERROR: See docs/faq.html for hints about trouble shooting. [5]PETSC ERROR: See docs/index.html for manual pages. [5]PETSC ERROR: ------------------------------------------------------------------------ [5]PETSC ERROR: /epi/asclepios2/bkhanal/works/AdLemModel/build/src/AdLemMain on a arch-linux2-cxx-debug named nef001 by bkhanal Wed Oct 16 15:08:42 2013 [5]PETSC ERROR: Libraries linked from /epi/asclepios2/bkhanal/petscDebug/lib [5]PETSC ERROR: Configure run at Wed Oct 16 14:18:48 2013 [5]PETSC ERROR: Configure options --with-mpi-dir=/opt/openmpi-gcc/current/ --with-shared-libraries --prefix=/epi/asclepios2/bkhanal/petscDebug -download-f-blas-lapack=1 --download-metis --download-parmetis --download-superlu_dist --download-scalapack --download-mumps --download-hypre --with-clanguage=cxx [5]PETSC ERROR: ------------------------------------------------------------------------ [5]PETSC ERROR: User provided function() line 0 in unknown directory unknown file [6]PETSC ERROR: ------------------------------------------------------------------------ [6]PETSC ERROR: Caught signal number 15 Terminate: Somet process (or the batch system) has told this process to end [6]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger [6]PETSC ERROR: or see http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind[6]PETSC ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS X to find memory corruption errors [6]PETSC ERROR: likely location of problem given in stack below [6]PETSC ERROR: --------------------- Stack Frames ------------------------------------ [6]PETSC ERROR: Note: The EXACT line numbers in the stack are not available, [6]PETSC ERROR: INSTEAD the line number of the start of the function [6]PETSC ERROR: is given. [6]PETSC ERROR: [6] HYPRE_SetupXXX line 130 /tmp/petsc-3.4.3/src/ksp/pc/impls/hypre/hypre.c [6]PETSC ERROR: [6] PCSetUp_HYPRE line 94 /tmp/petsc-3.4.3/src/ksp/pc/impls/hypre/hypre.c [6]PETSC ERROR: [6] PCSetUp line 868 /tmp/petsc-3.4.3/src/ksp/pc/interface/precon.c [6]PETSC ERROR: [6] KSPSetUp line 192 /tmp/petsc-3.4.3/src/ksp/ksp/interface/itfunc.c [6]PETSC ERROR: [6] KSPSolve line 356 /tmp/petsc-3.4.3/src/ksp/ksp/interface/itfunc.c [6]PETSC ERROR: [6] MatMult_SchurComplement line 75 /tmp/petsc-3.4.3/src/ksp/ksp/utils/schurm.c [6]PETSC ERROR: [6] MatNullSpaceTest line 408 /tmp/petsc-3.4.3/src/mat/interface/matnull.c [6]PETSC ERROR: [6] solveModel line 113 "unknowndirectory/"/epi/asclepios2/bkhanal/works/AdLemModel/src/PetscAdLemTaras3D.cxx 2. **************************************************************************************************** Using gamg instead has errors like following: [5]PETSC ERROR: --------------------- Stack Frames ------------------------------------ [5]PETSC ERROR: Note: The EXACT line numbers in the stack are not available, [5]PETSC ERROR: INSTEAD the line number of the start of the function [5]PETSC ERROR: is given. [5]PETSC ERROR: [5] PetscLLCondensedAddSorted line 1202 /tmp/petsc-3.4.3/include/petsc-private/matimpl.h [5]PETSC ERROR: [5] MatPtAPSymbolic_MPIAIJ_MPIAIJ line 124 /tmp/petsc-3.4.3/src/mat/impls/aij/mpi/mpiptap.c [5]PETSC ERROR: [5] MatPtAP_MPIAIJ_MPIAIJ line 80 /tmp/petsc-3.4.3/src/mat/impls/aij/mpi/mpiptap.c [5]PETSC ERROR: [5] MatPtAP line 8223 /tmp/petsc-3.4.3/src/mat/interface/matrix.c [5]PETSC ERROR: [5] createLevel line 144 /tmp/petsc-3.4.3/src/ksp/pc/impls/gamg/gamg.c [5]PETSC ERROR: [5] PCSetUp_GAMG line 545 /tmp/petsc-3.4.3/src/ksp/pc/impls/gamg/gamg.c [5]PETSC ERROR: [5] PCSetUp line 868 /tmp/petsc-3.4.3/src/ksp/pc/interface/precon.c [5]PETSC ERROR: [5] KSPSetUp line 192 /tmp/petsc-3.4.3/src/ksp/ksp/interface/itfunc.c [5]PETSC ERROR: [5] KSPSolve line 356 /tmp/petsc-3.4.3/src/ksp/ksp/interface/itfunc.c [5]PETSC ERROR: [5] MatMult_SchurComplement line 75 /tmp/petsc-3.4.3/src/ksp/ksp/utils/schurm.c [5]PETSC ERROR: [5] MatNullSpaceTest line 408 /tmp/petsc-3.4.3/src/mat/interface/matnull.c [5]PETSC ERROR: [5] solveModel line 113 "unknowndirectory/"/epi/asclepios2/bkhanal/works/AdLemModel/src/PetscAdLemTaras3D.cxx 3. ******************************************************************************************************** BUT, It does give me results when I use a domain of size: 91X109 X 91 (half sized in each dimension) The result along with ksp view in this case is as follows: Linear solve converged due to CONVERGED_RTOL iterations 2 KSP Object: 64 MPI processes type: gmres GMRES: restart=30, using Classical (unmodified) Gram-Schmidt Orthogonalization with no iterative refinement GMRES: happy breakdown tolerance 1e-30 maximum iterations=10000, initial guess is zero tolerances: relative=1e-05, absolute=1e-50, divergence=10000 left preconditioning has attached null space using PRECONDITIONED norm type for convergence test PC Object: 64 MPI processes type: fieldsplit FieldSplit with Schur preconditioner, blocksize = 4, factorization FULL Preconditioner for the Schur complement formed from user provided matrix Split info: Split number 0 Fields 0, 1, 2 Split number 1 Fields 3 KSP solver for A00 block KSP Object: (fieldsplit_0_) 64 MPI processes type: gmres GMRES: restart=30, using Classical (unmodified) Gram-Schmidt Orthogonalization with no iterative refinement GMRES: happy breakdown tolerance 1e-30 maximum iterations=10000, initial guess is zero tolerances: relative=1e-05, absolute=1e-50, divergence=10000 left preconditioning using PRECONDITIONED norm type for convergence test PC Object: (fieldsplit_0_) 64 MPI processes type: hypre HYPRE BoomerAMG preconditioning HYPRE BoomerAMG: Cycle type V HYPRE BoomerAMG: Maximum number of levels 25 HYPRE BoomerAMG: Maximum number of iterations PER hypre call 1 HYPRE BoomerAMG: Convergence tolerance PER hypre call 0 HYPRE BoomerAMG: Threshold for strong coupling 0.25 HYPRE BoomerAMG: Interpolation truncation factor 0 HYPRE BoomerAMG: Interpolation: max elements per row 0 HYPRE BoomerAMG: Number of levels of aggressive coarsening 0 HYPRE BoomerAMG: Number of paths for aggressive coarsening 1 HYPRE BoomerAMG: Maximum row sums 0.9 HYPRE BoomerAMG: Sweeps down 1 HYPRE BoomerAMG: Sweeps up 1 HYPRE BoomerAMG: Sweeps on coarse 1 HYPRE BoomerAMG: Relax down symmetric-SOR/Jacobi HYPRE BoomerAMG: Relax up symmetric-SOR/Jacobi HYPRE BoomerAMG: Relax on coarse Gaussian-elimination HYPRE BoomerAMG: Relax weight (all) 1 HYPRE BoomerAMG: Outer relax weight (all) 1 HYPRE BoomerAMG: Using CF-relaxation HYPRE BoomerAMG: Measure type local HYPRE BoomerAMG: Coarsen type Falgout HYPRE BoomerAMG: Interpolation type classical linear system matrix = precond matrix: Matrix Object: 64 MPI processes type: mpiaij rows=2793120, cols=2793120 total: nonzeros=221624352, allocated nonzeros=221624352 total number of mallocs used during MatSetValues calls =0 using I-node (on process 0) routines: found 14812 nodes, limit used is 5 KSP solver for S = A11 - A10 inv(A00) A01 KSP Object: (fieldsplit_1_) 64 MPI processes type: gmres GMRES: restart=30, using Classical (unmodified) Gram-Schmidt Orthogonalization with no iterative refinement GMRES: happy breakdown tolerance 1e-30 maximum iterations=10000, initial guess is zero tolerances: relative=1e-05, absolute=1e-50, divergence=10000 left preconditioning has attached null space using PRECONDITIONED norm type for convergence test PC Object: (fieldsplit_1_) 64 MPI processes type: bjacobi block Jacobi: number of blocks = 64 Local solve is same for all blocks, in the following KSP and PC objects: KSP Object: (fieldsplit_1_sub_) 1 MPI processes type: preonly maximum iterations=10000, initial guess is zero tolerances: relative=1e-05, absolute=1e-50, divergence=10000 left preconditioning using NONE norm type for convergence test PC Object: (fieldsplit_1_sub_) 1 MPI processes type: ilu ILU: out-of-place factorization 0 levels of fill tolerance for zero pivot 2.22045e-14 using diagonal shift on blocks to prevent zero pivot [INBLOCKS] matrix ordering: natural factor fill ratio given 1, needed 1 Factored matrix follows: Matrix Object: 1 MPI processes type: seqaij rows=14812, cols=14812 package used to perform factorization: petsc total: nonzeros=368098, allocated nonzeros=368098 total number of mallocs used during MatSetValues calls =0 not using I-node routines linear system matrix = precond matrix: Matrix Object: 1 MPI processes type: seqaij rows=14812, cols=14812 total: nonzeros=368098, allocated nonzeros=368098 total number of mallocs used during MatSetValues calls =0 not using I-node routines linear system matrix followed by preconditioner matrix: Matrix Object: 64 MPI processes type: schurcomplement rows=931040, cols=931040 Schur complement A11 - A10 inv(A00) A01 A11 Matrix Object: 64 MPI processes type: mpiaij rows=931040, cols=931040 total: nonzeros=24624928, allocated nonzeros=24624928 total number of mallocs used during MatSetValues calls =0 not using I-node (on process 0) routines A10 Matrix Object: 64 MPI processes type: mpiaij rows=931040, cols=2793120 total: nonzeros=73874784, allocated nonzeros=73874784 total number of mallocs used during MatSetValues calls =0 not using I-node (on process 0) routines KSP of A00 KSP Object: (fieldsplit_0_) 64 MPI processes type: gmres GMRES: restart=30, using Classical (unmodified) Gram-Schmidt Orthogonalization with no iterative refinement GMRES: happy breakdown tolerance 1e-30 maximum iterations=10000, initial guess is zero tolerances: relative=1e-05, absolute=1e-50, divergence=10000 left preconditioning using PRECONDITIONED norm type for convergence test PC Object: (fieldsplit_0_) 64 MPI processes type: hypre HYPRE BoomerAMG preconditioning HYPRE BoomerAMG: Cycle type V HYPRE BoomerAMG: Maximum number of levels 25 HYPRE BoomerAMG: Maximum number of iterations PER hypre call 1 HYPRE BoomerAMG: Convergence tolerance PER hypre call 0 HYPRE BoomerAMG: Threshold for strong coupling 0.25 HYPRE BoomerAMG: Interpolation truncation factor 0 HYPRE BoomerAMG: Interpolation: max elements per row 0 HYPRE BoomerAMG: Number of levels of aggressive coarsening 0 HYPRE BoomerAMG: Number of paths for aggressive coarsening 1 HYPRE BoomerAMG: Maximum row sums 0.9 HYPRE BoomerAMG: Sweeps down 1 HYPRE BoomerAMG: Sweeps up 1 HYPRE BoomerAMG: Sweeps on coarse 1 HYPRE BoomerAMG: Relax down symmetric-SOR/Jacobi HYPRE BoomerAMG: Relax up symmetric-SOR/Jacobi HYPRE BoomerAMG: Relax on coarse Gaussian-elimination HYPRE BoomerAMG: Relax weight (all) 1 HYPRE BoomerAMG: Outer relax weight (all) 1 HYPRE BoomerAMG: Using CF-relaxation HYPRE BoomerAMG: Measure type local HYPRE BoomerAMG: Coarsen type Falgout HYPRE BoomerAMG: Interpolation type classical linear system matrix = precond matrix: Matrix Object: 64 MPI processes type: mpiaij rows=2793120, cols=2793120 total: nonzeros=221624352, allocated nonzeros=221624352 total number of mallocs used during MatSetValues calls =0 using I-node (on process 0) routines: found 14812 nodes, limit used is 5 A01 Matrix Object: 64 MPI processes type: mpiaij rows=2793120, cols=931040 total: nonzeros=73874784, allocated nonzeros=73874784 total number of mallocs used during MatSetValues calls =0 using I-node (on process 0) routines: found 14812 nodes, limit used is 5 Matrix Object: 64 MPI processes type: mpiaij rows=931040, cols=931040 total: nonzeros=24624928, allocated nonzeros=24624928 total number of mallocs used during MatSetValues calls =0 not using I-node (on process 0) routines linear system matrix = precond matrix: Matrix Object: 64 MPI processes type: mpiaij rows=3724160, cols=3724160, bs=4 total: nonzeros=393998848, allocated nonzeros=393998848 total number of mallocs used during MatSetValues calls =0 ****************************************************************************************************** What could be going wrong here ? Is it something related to null-space setting ? But I do not know why it does not arise for smaller domain sizes!
