[petsc-dev] [EXTERNAL] Re: external preconditioner availablilty for PETSc

[Jed Brown]

Yeah, I wouldn't get bogged down in that.  I would work on the good
methods and then use as a reference those components without the
composition.  For example, you might use Hypre's BoomerAMG inside a
composed preconditioner.  You could run it on its own to show that the
chosen structure was important.

"Hammond, Glenn E" <gehammo at sandia.gov> writes:

> Jed,
>
> For the proposal, Heeho wants to demonstrate that a (well?) tuned black box preconditioner does not perform well (e.g. ILU[k], ILU[dt]).  Ultimately, he plans to build on work by Qang Bui (currently a post-doc at  LLNL), which is aligned with what you propose below, e.g.
>
> Bui, Quan & Wang, Lu & Osei-Kuffuor, Daniel. (2018). Algebraic Multigrid Preconditioners for Two-phase Flow in Porous Media with Phase Transitions. Advances in Water Resources. 114. 10.1016/j.advwatres.2018.01.027.
> Bui, Quan & C. Elman, Howard & Moulton, J. (2016). Algebraic Multigrid Preconditioners for Multiphase Flow in Porous Media. SIAM Journal on Scientific Computing. 39. 10.1137/16M1082652.
>
> So, at this point, Heeho is looking for the best out-of-the-box preconditioners to demonstrate their poor performance.  Or perhaps he should just employ PETSc's ILU[k] and move on.... 
>
> Glenn
>
>> -----Original Message-----
>> From: Jed Brown <jed at jedbrown.org>
>> Sent: Tuesday, March 5, 2019 9:06 PM
>> To: Park, Heeho <heepark at sandia.gov>; petsc-dev at mcs.anl.gov
>> Cc: Park, Heeho Daniel <hdpark2 at illinois.edu>; Hammond, Glenn E
>> <gehammo at sandia.gov>
>> Subject: [EXTERNAL] Re: [petsc-dev] external preconditioner availablilty for
>> PETSc
>> 
>> From a research perspective, it doesn't make sense to view these
>> preconditioners as black boxes.  Your problem will likely have an elliptic
>> component (which you might approach using a multilevel method such as
>> PCGAMG, PCML, PCHYPRE, or PCBDDC, all of which can accept some
>> problem-specific input information as well as tunable parameters) combined
>> (perhaps using PCFIELDSPLIT) with a transport solver (perhaps one-level
>> domain decomposition).  The details of the splits will take some thought and
>> you'll want to compare to monolithic (unsplit) 1-level domain decomposition
>> methods with suitably chosen subdomains and/or geometric multigrid.  One
>> way to start would be to do a literature search and try to reproduce the
>> results from some methods in the literature.  After that, you'll have a
>> baseline for comparison and probably get some ideas about composition.
>> 
>> "Park, Heeho via petsc-dev" <petsc-dev at mcs.anl.gov> writes:
>> 
>> > Hi PETSc developers,
>> >
>> > I’m writing my proposal for my dissertation research at UIUC that will study
>> on effectiveness of preconditioners for anisothermal, multiphase porous
>> media flow calculations in parallel using PFLOTRAN. I know the link below lists
>> preconditioners but from your experience, which preconditioning packages
>> provide reliable and efficient PILUT, AMG, SA-AMG preconditioners for
>> PETSc and do you have other preconditioner recommendations?
>> > I used hypre PILUT, but the performance and the linear iteration count to
>> solve a matrix is worse than ILU(0) which is not what I expected.
>> >
>> > https://www.mcs.anl.gov/petsc/documentation/linearsolvertable.html
>> >
>> > Heeho Daniel Park
>> >
>> > ! ------------------------------------ !
>> > Sandia National Laboratories
>> > Org: 08844, R&D
>> > Work: 505-844-1319
>> > ! ------------------------------------ !