SNESSetUp() and matrix-free options

[Lisandro Dalcin]

First of all, I'm very sorry about this... I just didn't noticed...
How can I have access to the nightly tests?

On Tue, Jul 21, 2009 at 1:09 PM, Barry Smith<bsmith at mcs.anl.gov> wrote:
>
>    Your moving of the -snes_mf options to SNESSetFromOptions() has broken
> PETSc.
>



> [bsmith-laptop:ts/examples/tests] barrysmith% make runex4_2
> Possible problem with ex4_2, diffs above
>
>   Please fix!
>

Done. Comments below...

> This has been broken for a long time and broken things mean no
> one checks the nightly builds which means more and more things break.
>

Too bad. I ask again: How can I access the nightly builds? Take for
sure that If I would have access to such results, I would fix my
faults almost immediately... I just did not know about this situation
(BTW, many thanks).

> In SNESSetFromOptions() you have
>
>
>  if (mf) { ierr = SNESSetUpMatrixFree_Private(snes, mf_operator,
> mf_version);CHKERRQ(ierr); }
>
> as my email says in May this is a problem. I think the easiest fix is to
> save the mf flags in the SNES data structure and call
> SNESSetUpMatrixFree_Private()
> as it use to be called in SNESSetUp(). Perhaps there is a problem with that
> fix I do not know about.
>

Well Barry, the way you are suggesting is not going to actually 100%
fix things, but just mask other broken parts... Let me elaborate:

- SNESSetFromOptions() calls KSPSetFromOptions()
- but before calling KSPSetFromOptions(), you sould call
KSPSetOperators() (in order to let KSP pick good defaults)
- then we should build the MFFD Jacobian at SNESSetFromOptions()...

Do you agree with my rationale?

So I pushed a quick fix that makes the TS tests pass, but IMHO you
should follow one of:

- "hg backout" my commits (first "b17fe4b08207" and next
"6fcd5defc59c"), and forget about the whole thing.

- we should discuss deeper this whole stuff of having
SetFromOptions()/SetUp()/Solve() calls in KSP/SNES/TS; define the
rules, and review and fix any place that does not follow the rules.



>
> Begin forwarded message:
>
>> From: Barry Smith <bsmith at mcs.anl.gov>
>> Date: May 6, 2009 3:25:43 PM CDT
>> To: For users of the development version of PETSc <petsc-dev at mcs.anl.gov>
>> Subject: Re: SNESSetUp() and matrix-free options
>>
>>
>>  Lisandro,
>>
>>    The checking of the options can be moved to SNESSetFromOptions() that
>> then set some flag in the snes object;
>> but the actual action of MatCreateSNESMF() etc must continue to take place
>> in the setup.
>>
>>   Feel free to change if you like,
>>
>>  Barry
>>
>>
>> On May 6, 2009, at 3:15 PM, Lisandro Dalcin wrote:
>>
>>> Currently, -snes_mf* options are handled in SNESSetUp()... I think all
>>> you will agree that the proper place for them is
>>> SNESSetFromOptions()... However, perhaps I'm missing something and
>>> things are like that for some reason... In that case I would like to
>>> know the reason and perhaps I could fix this...
>>>
>>> --
>>> Lisandro Dalcín
>>> ---------------
>>> Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
>>> Instituto de Desarrollo Tecnológico para la Industria Química (INTEC)
>>> Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
>>> PTLC - Güemes 3450, (3000) Santa Fe, Argentina
>>> Tel/Fax: +54-(0)342-451.1594
>>
>
>



-- 
Lisandro Dalcín
---------------
Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
Instituto de Desarrollo Tecnológico para la Industria Química (INTEC)
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
PTLC - Güemes 3450, (3000) Santa Fe, Argentina
Tel/Fax: +54-(0)342-451.1594