[petsc-users] Hypre BoomerAMG settings options database

[Mark Adams]

I was thinking about interpreting the "BoomerAMG SOLVER PARAMETERS:" stuff
(eg, what is the closest thing to SSOR that Parv wants).
That does not look like our code, but maybe it is.

On Sat, Jan 6, 2024 at 12:50 PM Pierre Jolivet <pierre at joliv.et> wrote:

>
>
> On 6 Jan 2024, at 3:15 PM, Mark Adams <mfadams at lbl.gov> wrote:
>
> Does this work for you?
>
> -pc_hypre_boomeramg_grid_sweeps_all 2
>
> The comment in our code says SSOR is the default but it looks like it is really "hSGS"
>
> I thought it was an L1 Jacobi, but you would want to ask Hypre about this.
>
> HYPRE’s default settings are not the same as the ones we set in PETSc as
> default, so do not ask HYPRE people (about this particular issue).
>
> Thanks,
> Pierre
>
> Mark
>
>
>
> On Fri, Jan 5, 2024 at 10:21 AM Barry Smith <bsmith at petsc.dev> wrote:
>
>>
>>   Yes, the handling of BoomerAMG options starts at line 365. If we don't
>> support what you want but hypre has a function call that allows one to set
>> the values then the option could easily be added to the PETSc options
>> database here either by you (with a merge request) or us. So I would say
>> check the hypre docs.
>>
>>   Just let us know what BoomerAMG function is missing from the code.
>>
>>   Barry
>>
>>
>> On Jan 5, 2024, at 7:52 AM, Khurana, Parv <p.khurana22 at imperial.ac.uk>
>> wrote:
>>
>> 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
>>
>>
>>
>
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