[petsc-users] Using nonzero -pc_hypre_boomeramg_restriction_type in field split
Alexander Lindsay
alexlindsay239 at gmail.com
Sun Apr 16 18:10:52 CDT 2023
Are there any plans to get the missing hook into PETSc for AIR? Just curious if there’s an issue I can subscribe to or anything.
(Independently I’m excited to test HPDDM out tomorrow)
> On Apr 13, 2023, at 10:29 PM, Pierre Jolivet <pierre.jolivet at lip6.fr> wrote:
>
>
>> On 14 Apr 2023, at 7:02 AM, Alexander Lindsay <alexlindsay239 at gmail.com> wrote:
>>
>> Pierre,
>>
>> This is very helpful information. Thank you. Yes I would appreciate those command line options if you’re willing to share!
>
> No problem, I’ll get in touch with you in private first, because it may require some extra work (need a couple of extra options in PETSc ./configure), and this is not very related to the problem at hand, so best not to spam the mailing list.
>
> Thanks,
> Pierre
>
>>>> On Apr 13, 2023, at 9:54 PM, Pierre Jolivet <pierre.jolivet at lip6.fr> wrote:
>>>>
>>>
>>>
>>>> On 13 Apr 2023, at 10:33 PM, Alexander Lindsay <alexlindsay239 at gmail.com> wrote:
>>>>
>>>> Hi, I'm trying to solve steady Navier-Stokes for different Reynolds numbers. My options table
>>>>
>>>> -dm_moose_fieldsplit_names u,p
>>>> -dm_moose_nfieldsplits 2
>>>> -fieldsplit_p_dm_moose_vars pressure
>>>> -fieldsplit_p_ksp_type preonly
>>>> -fieldsplit_p_pc_type jacobi
>>>> -fieldsplit_u_dm_moose_vars vel_x,vel_y
>>>> -fieldsplit_u_ksp_type preonly
>>>> -fieldsplit_u_pc_hypre_type boomeramg
>>>> -fieldsplit_u_pc_type hypre
>>>> -pc_fieldsplit_schur_fact_type full
>>>> -pc_fieldsplit_schur_precondition selfp
>>>> -pc_fieldsplit_type schur
>>>> -pc_type fieldsplit
>>>>
>>>> works wonderfully for a low Reynolds number of 2.2. The solver performance crushes LU as I scale up the problem. However, not surprisingly this options table struggles when I bump the Reynolds number to 220. I've read that use of AIR (approximate ideal restriction) can improve performance for advection dominated problems. I've tried setting -pc_hypre_boomeramg_restriction_type 1 for a simple diffusion problem and the option works fine. However, when applying it to my field-split preconditioned Navier-Stokes system, I get immediate non-convergence:
>>>>
>>>> 0 Nonlinear |R| = 1.033077e+03
>>>> 0 Linear |R| = 1.033077e+03
>>>> Linear solve did not converge due to DIVERGED_NANORINF iterations 0
>>>> Nonlinear solve did not converge due to DIVERGED_LINEAR_SOLVE iterations 0
>>>>
>>>> Does anyone have an idea as to why this might be happening?
>>>
>>> Do not use this option, even when not part of PCFIELDSPLIT.
>>> There is some missing plumbing in PETSc which makes it unusable, see Ben’s comment here https://github.com/hypre-space/hypre/issues/764#issuecomment-1353452417.
>>> In fact, it’s quite easy to make HYPRE generate NaN with a very simple stabilized convection—diffusion problem near the pure convection limit (something that ℓAIR is supposed to handle).
>>> Even worse, you can make HYPRE fill your terminal with printf-style debugging messages https://github.com/hypre-space/hypre/blob/5546cc22d46b3dba253849f258786da47c9a7b21/src/parcsr_ls/par_lr_restr.c#L1416 with this option turned on.
>>> As a result, I have been unable to reproduce any of the ℓAIR results.
>>> This also explains why I have been using plain BoomerAMG instead of ℓAIR for the comparison in page 9 of https://arxiv.org/pdf/2201.02250.pdf (if you would like to try the PC we are using, I could send you the command line options).
>>>
>>> Thanks,
>>> Pierre
>>>
>>>> If not, I'd take a suggestion on where to set a breakpoint to start my own investigation. Alternatively, I welcome other preconditioning suggestions for an advection dominated problem.
>>>>
>>>> Alex
>>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20230416/1b819c57/attachment-0001.html>
More information about the petsc-users
mailing list