Jed, No the matrix is actually non-symmetric due to grid adaptivity (hanging nodes of QuadTree). Anyway, what do you exactly mean by the system being inconsistent?
On Thu, Mar 6, 2014 at 3:49 PM, Mohammad Mirzadeh <[email protected]>wrote: > 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 <[email protected]> wrote: > >> Mohammad Mirzadeh <[email protected]> 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. >> > >
