[petsc-dev] explaining hierarchical composible solvers

[Matthew Knepley]

On Mon, Dec 3, 2012 at 12:30 AM, Karl Rupp <rupp at mcs.anl.gov> wrote:
> which doesn't surprise me. Maybe GUI programming tools are now sufficiently
> mature and powerful such that they indeed help to reduce the overall
> complexity instead of only adding an additional maintenance burden?

I used to believe this. Or maybe something closer to "code artifacts can be
independently extracted, manipulated easily, and recombined to make coding
easier" which was the program at MS run by the Hungarian notation guy. Barry
definitely believed this too. Unfortunately, all our attempts failed miserably,
and facts are pretty convincing. Unless we want to turn into the
parallel compiler
guys, we have to look at the facts on the ground.

I do think Barry is right here that the best use of visualization is
to comprehend
overall structure and diagnose logic errors, rather than construct code itself.

   Matt

> Best regards,
> Karli
>
>
>
>
> On 12/02/2012 11:51 PM, Jed Brown wrote:
>>
>> Not a new idea, my friend.
>>
>>
>> On Sun, Dec 2, 2012 at 9:49 PM, Karl Rupp <rupp at mcs.anl.gov
>> <mailto:rupp at mcs.anl.gov>> wrote:
>>
>>     Hmm, following this thought/path all the way down should lead us to
>> ...
>>
>>     ... a PETSc GUI? It surely sounds a bit odd, but at some point every
>>     means to fight the dragon named complexity is welcome.
>>
>>     Best regards,
>>     Karli
>>
>>
>>
>>
>>     On 12/02/2012 07:55 PM, Jed Brown wrote:
>>
>>         I have wanted to make this sort of view interactive for a long
>> time.
>>
>>         On Dec 2, 2012 4:48 PM, "Barry Smith" <bsmith at mcs.anl.gov
>>         <mailto:bsmith at mcs.anl.gov>
>>         <mailto:bsmith at mcs.anl.gov <mailto:bsmith at mcs.anl.gov>>> wrote:
>>
>>
>>
>>
>>
>>              In order to help explain and understand composible solver I
>>         started
>>              to add the PetscViewerDraw ability to the solver objects to
>>              graphically explain the solvers used and the decomposition
>>         of the
>>              solvers. It is very crude now but I've attached a couple of
>>         images
>>              of what are generated when using -ts/snes/ksp_view_draw
>>         We need to
>>              add more information (somehow) to indicate  the multigrid
>>         levels as
>>              "levels" the field split decomposition etc. Any thoughts or
>>         code
>>              welcome.
>>
>>                  Barry
>>
>>
>>
>>
>>
>



--
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which
their experiments lead.
-- Norbert Wiener