Hello PETSc users community,

Happy new year! Thank you for the community support as always.

I am using BoomerAMG for my research, and it is interfaced to my software via PETSc. I can only use options database keys as of now to tweak the settings I want for the AMG solve.

I want to control the number of smoothener iterations at pre/post step for a given AMG cycle. I am looking for an options database key which helps me control this. I am not sure whether this is possible directly via the keys (Line 365: https://www.mcs.anl.gov/petsc/petsc-3.5.4/src/ksp/pc/impls/hypre/hypre.c.html). My comprehension of the current setup is that I have 1 smoothener iteration at every coarsening step. My aim is to do two pre and 2 post smoothening steps using the SSOR smoothener.

BoomerAMG SOLVER PARAMETERS:

  Maximum number of cycles:         1

  Stopping Tolerance:               0.000000e+00

  Cycle type (1 = V, 2 = W, etc.):  1

  Relaxation Parameters:

   Visiting Grid:                     down   up  coarse

            Number of sweeps:            1    1     1

   Type 0=Jac, 3=hGS, 6=hSGS, 9=GE:      6    6     9

   Point types, partial sweeps (1=C, -1=F):

                  Pre-CG relaxation (down):   1  -1

                   Post-CG relaxation (up):  -1   1

                             Coarsest grid:   0

PETSC settings I am using currently:

-ksp_type preonly

-pc_type hypre

-pc_hypre_type boomeramg

-pc_hypre_boomeramg_coarsen_type hmis

-pc_hypre_boomeramg_relax_type_all symmetric-sor/jacobi

-pc_hypre_boomeramg_strong_threshold 0.7

-pc_hypre_boomeramg_interp_type ext+i

-pc_hypre_boomeramg_P_max 2

-pc_hypre_boomeramg_truncfactor 0.3

Thanks and Best

Parv Khurana