Thank you, Barry. You must be right in this case. I am defaulting to ILU.
I did an additional test to confirm, with ‘-pc_type ilu’ in the command line,
it works fine.
If I am defaulting to ILU, when should I call PCFactorSetMatOrderingType?
-Ling
From: Barry Smith <bsm...@petsc.dev>
Date: Sunday, August 18, 2024 at 12:22 PM
To: Zou, Ling <l...@anl.gov>
Cc: petsc-users@mcs.anl.gov <petsc-users@mcs.anl.gov>
Subject: Re: [petsc-users] PCFactorSetMatOrderingType not working with 3.21
Are you using -pc_type ilu at the command line in your test? Or just letting it
default to using ILU? This could explain the difference, the decision of what
preconditioner to default to has moved until later in code, not when the PC is
created
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Are you using -pc_type ilu at the command line in your test? Or just
letting it default to using ILU?
This could explain the difference, the decision of what preconditioner to
default to has moved until later in code, not when the PC is created or the
matrix supplied but when it starts to build the preconditioner. Hence when you
call PCFactorSetMatOrderingType() in the code the PC may not yet be set to ILU
(or anything) hence the PCFactorSetMatOrderingType() is ignored,
On Aug 17, 2024, at 3:44 PM, Zou, Ling <l...@anl.gov> wrote:
Barry, thanks.
I am accessing PETSc through MOOSE. I need to figure out if the versions are
consistent and how to test it.
-Ling
From: Barry Smith <bsm...@petsc.dev<mailto:bsm...@petsc.dev>>
Date: Saturday, August 17, 2024 at 12:08 PM
To: Zou, Ling <l...@anl.gov<mailto:l...@anl.gov>>
Cc: petsc-users@mcs.anl.gov<mailto:petsc-users@mcs.anl.gov>
<petsc-users@mcs.anl.gov<mailto:petsc-users@mcs.anl.gov>>
Subject: Re: [petsc-users] PCFactorSetMatOrderingType not working with 3.21
I have attached src/snes/tutorials/ex5. c in which I tried to reproduce your
problem by inserting the code you've indicated. However I am not getting the
problem you see, I am seeing, type: ilu out-of-place factorization 0 levels of
fill tolerance
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I have attached src/snes/tutorials/ex5.c in which I tried to reproduce your
problem by inserting the code you've indicated.
However I am not getting the problem you see, I am seeing,
type: ilu
out-of-place factorization
0 levels of fill
tolerance for zero pivot 2.22045e-14
matrix ordering: rcm
when I run with -pc_type ilu -snes_view
Can you please confirm you get the same problem with the attached ex5.c ? You
could send your code to see if I can reproduce the problem.
I am using the release branch of PETSc
Barry
On Aug 17, 2024, at 12:35 PM, Zou, Ling via petsc-users
<petsc-users@mcs.anl.gov<mailto:petsc-users@mcs.anl.gov>> wrote:
Hi all,
The following codes are how I used to setup PC mat ordering:
// Setup KSP/PC (at this moment, user-input options and commandline options
are available)
SNESGetKSP(snes, &ksp);
KSPSetFromOptions(ksp);
PC pc;
KSPGetPC(ksp, &pc);
PCFactorSetMatOrderingType(pc, MATORDERINGRCM);
// PCFactorSetLevels(pc, 5);
SNESSetFromOptions(snes);
After switching to PETSc 3.21, this no longer works, and can be confirmed from
‘-snes_view’ output:
PC Object: 1 MPI process
type: ilu
out-of-place factorization
0 levels of fill
tolerance for zero pivot 2.22045e-14
using diagonal shift to prevent zero pivot [NONZERO]
matrix ordering: natural
The command line option still works, i.e., ‘-pc_factor_mat_ordering_type rcm’
gives me the correct behavior.
Questions:
* Is this a bug introduced in the new version, or
* With the new version, I should call this function at a different time?
Best,
-Ling
