Thanks, Barry.
On Mon, Sep 5, 2016 at 11:26 AM, Barry Smith <[email protected]> wrote: > > > On Sep 5, 2016, at 11:21 AM, Fande Kong <[email protected]> wrote: > > > > Hi Developers, > > > > There are two questions on the hypre preconditioner. > > > > (1) How to set different relax types on different levels? It looks to > use the SAME relax type on all levels except the coarse level which we > could set it to a different solver. Especially, could I set the smoother > type on the finest level as NONE? > > I don't think this is possible through the PETSc interface; it may or > may not be possible by adding additional hypre calls. You need to check the > hypre documentation. > I already took a look into the hypre code. It is not easy to change. But there is a way to do that. I already figured out a way to extract interpolation, restriction and coarse operators from hypre. I could construct any algorithms I want with these operators. The question is: any existing ways to convert a parallel hypre matrix to a petsc Mat, and the same operations for vectors? > > > > > (2) How could I know how many levels have been actually created in > hypre, and how many unknowns on different levels? The "-pc_view" can not > tell me this information: > > -pc_hypre_boomeramg_print_statistics integer different integers give > different amounts of detail, I don't know what the integers mean. > we could get all information by extracting data from hypre_solver. Fande, > > > > > > > > > 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: > > > > > > > > Fande, > >
