Matt, here's the output:
0 KSP Residual norm 3.033840960250e+02 1 KSP Residual norm 1.018974811826e+01 2 KSP Residual norm 5.450493684941e-02 3 KSP Residual norm 3.944064039516e-02 4 KSP Residual norm 6.286181172600e-05 5 KSP Residual norm 4.349133658643e-06 6 KSP Residual norm 9.279429568232e-08 7 KSP Residual norm 3.032522248740e-09 8 KSP Residual norm 6.533747246875e-09 9 KSP Residual norm 6.083185162500e-12 Linear solve converged due to CONVERGED_RTOL iterations 9 KSP Object: 1 MPI processes type: bcgs maximum iterations=10000, initial guess is zero tolerances: relative=1e-12, absolute=1e-50, divergence=10000 left preconditioning has attached null space using PRECONDITIONED norm type for convergence test PC Object: 1 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 0.5 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 symmetric-SOR/Jacobi 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: Mat Object: 1 MPI processes type: seqaij rows=263169, cols=263169 total: nonzeros=1236141, allocated nonzeros=1244417 total number of mallocs used during MatSetValues calls =0 has attached null space not using I-node routines On Thu, Mar 6, 2014 at 3:43 PM, Jed Brown <j...@jedbrown.org> wrote: > Mohammad Mirzadeh <mirza...@gmail.com> writes: > > > Yes. To be precise this is the set of functions I call: > > > > ierr = MatNullSpaceCreate(mpicomm, PETSC_FALSE, 1, &null_space, > > &A_null_space); CHKERRXX(ierr); > > > > ierr = MatSetNullSpace(A, A_null_space); CHKERRXX(ierr); > > > > ierr = KSPSetNullSpace(ksp, A_null_space); CHKERRXX(ierr); > > > > ierr = MatNullSpaceRemove(A_null_space, rhs_, NULL); CHKERRXX(ierr); > > Is the matrix symmetric? If not, the right and left null spaces could > be different, in which case this system might be inconsistent. >