convergence of BoomerAMG
stijn vantieghem
stvtiegh at ulb.ac.be
Mon Nov 17 06:04:48 CST 2008
Dear PETSc team
I'm using PETSC with HYPRE's BoomerAMG to solve a pressure Poisson
equation in an incompressible Navier-Stokes solver. When working on a
64x129x64-grid, it converges reasonbly well on 8 (1 bi-quad-core)
processors, However, when changing. to 16 (2 bi-quad-core) procs,
BoomerAMG is hardly able to converge. Below, you find an excerpt of my
code with all the flags I'm using . Have you any suggestions to
overcome this problem?
Thanks in advance
Sincerely yours
Stijn Vantieghem
! KSP parameters
call KSPCreate(PETSC_COMM_WORLD,ksp,ierr)
call KSPSetType(ksp,KSPRICHARDSON,ierr)
call KSPSetOperators(ksp,M,M,DIFFERENT_NONZERO_PATTERN,ierr)
call KSPGetPC(ksp,pc,ierr)
call PCSetType(pc,PCHYPRE,ierr)
call PCHYPRESetType(pc,"boomeramg",ierr)
! HYPRE Options
call PetscOptionsSetValue("-
pc_hypre_boomeramg_print_statistics","2",ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_tol",trim(co),ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_max_iter","25",ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_min_iter","2",ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_grid_sweeps_down","2",ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_grid_sweeps_up","2",ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_grid_sweeps_coarse","1",ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_relax_type_down","SOR/Jacobi",ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_relax_type_up","SOR/Jacobi",ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_relax_type_coarse","Jacobi",ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_relax_weight_all","1.0",ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_outer_relax_weight_all","1.0",ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_grid_sweeps_all","1",ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_max_row_sum","1.0",ierr)
call PetscOptionsSetValue("-
pc_hypre_boomeramg_max_levels","25",ierr)
! call PetscOptionsSetValue("-
pc_hypre_boomeramg_nodal_coarsen",PETSC_NULL_CHARACTER,ierr)
call KSPSetTolerances(ksp,1.0e-10_WP,1.0e-6_WP,1.0e15_WP,
1,ierr)
call KSPSetFromOptions(ksp,ierr)
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