A little more info... if I destroy the PC object (with PCDestory()) and
recreate it then everything works fine... but this is non-ideal as that is
happening for every nonlinear iteration (this is in
PetscPreconditioner::init() in libMesh).
Derek
On Mon, Feb 4, 2013 at 3:20 PM, Derek Gaston <fried...@gmail.com> wrote:
> Thanks Jed.... PCReset() somewhat fixed it... but now I get this:
>
> [0]PETSC ERROR: Error in external library!
> [0]PETSC ERROR: Error in HYPRE_IJMatrixAssemble()!
> ...
> [0]PETSC ERROR: MatHYPRE_IJMatrixFastCopy_SeqAIJ() line 183 in
> src/dm/impls/da/hypre/mhyp.c
> [0]PETSC ERROR: MatHYPRE_IJMatrixCopy() line 127 in
> src/dm/impls/da/hypre/mhyp.c
> [0]PETSC ERROR: PCSetUp_HYPRE() line 118 in src/ksp/pc/impls/hypre/hypre.c
> [0]PETSC ERROR: PCSetUp() line 832 in src/ksp/pc/interface/precon.c
> [0]PETSC ERROR: PCApply() line 380 in src/ksp/pc/interface/precon.c
> [0]PETSC ERROR: apply() line 53 in
> "unknowndirectory/"src/numerics/petsc_preconditioner.C
>
> Looks like maybe PCReset() doesn't work properly with Hypre?
>
> As for why this worked before and isn't now... I have no idea. We were
> definitely changing the system size all the time with adaptivity... and
> never saw this before...
>
> Derek
>
>
>
> On Mon, Feb 4, 2013 at 2:56 PM, Jed Brown <jedbr...@mcs.anl.gov> wrote:
>
>> On Mon, Feb 4, 2013 at 3:44 PM, Derek Gaston <fried...@gmail.com> wrote:
>>
>>> After updating to Petsc 3.3 (and the new libMesh... so it's not clear
>>> where the error is). One of our fancier preconditioning routines that
>>> relies on matrices added using system.add_matrix() calls is failing when we
>>> try to apply the preconditioner with an error that says:
>>>
>>> [0]PETSC ERROR: PCSetOperators() line 1049 in
>>> src/ksp/pc/interface/precon.c Cannot change local size of Amat after use
>>> old sizes 9 9 new sizes 25 25
>>>
>>> This is in an adaptivity problem that starts out with 2x2 quads (hence
>>> the 9x9 nature of the original matrix) and is being adapted (25x25 sounds
>>> right).
>>>
>>> Anyone seen this before? Is this some new checking in PETSc that is
>>> getting tripped...
>>>
>>
>> PETSc has never supported changing the system size arbitrarily, but if
>> you set the matrix and changed it _before_ setting up the preconditioner,
>> you would have been okay in the past. We likely added the check when we
>> added PCReset (and KSPReset, etc). This tells PETSc to rebuild any
>> size-dependent structures, but does not change configuration. If you call
>> this before setting a new operator with different sizes, you should be fine.
>>
>> If the code worked before, perhaps you never used the PC to solve a
>> smaller system before calling PCSetOperators() with a new system.
>>
>>
>>> or is libMesh possibly not resizing these matrices correctly?
>>>
>>> I'll provide more information as I have it... I just thought I would see
>>> if anyone had run into this before I get too deep in here...
>>>
>>> Derek
>>>
>>>
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>>
>
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