[petsc-users] Why use MATMPIBAIJ?

[Matthew Knepley]

On Fri, Jan 22, 2016 at 9:27 AM, Mark Adams <mfadams at lbl.gov> wrote:

>
>>
>> I said the Hypre setup cost is not scalable,
>>
>
> I'd be a little careful here.  Scaling for the matrix triple product is
> hard and hypre does put effort into scaling. I don't have any data
> however.  Do you?
>

I used it for PyLith and saw this. I did not think any AMG had scalable
setup time.

   Matt


> but it can be amortized over the iterations. You can quantify this
>> just by looking at the PCSetUp time as your increase the number of
>> processes. I don't think they have a good
>> model for the memory usage, and if they do, I do not know what it is.
>> However, generally Hypre takes more
>> memory than the agglomeration MG like ML or GAMG.
>>
>>
> agglomerations methods tend to have lower "grid complexity", that is
> smaller coarse grids, than classic AMG like in hypre. THis is more of a
> constant complexity and not a scaling issue though.  You can address this
> with parameters to some extent. But for elasticity, you want to at least
> try, if not start with, GAMG or ML.
>
>
>>   Thanks,
>>
>>     Matt
>>
>>
>>>
>>> Giang
>>>
>>> On Mon, Jan 18, 2016 at 5:25 PM, Jed Brown <jed at jedbrown.org> wrote:
>>>
>>>> Hoang Giang Bui <hgbk2008 at gmail.com> writes:
>>>>
>>>> > Why P2/P2 is not for co-located discretization?
>>>>
>>>> Matt typed "P2/P2" when me meant "P2/P1".
>>>>
>>>
>>>
>>
>>
>> --
>> 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
>>
>
>


-- 
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
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