[petsc-dev] asm / gasm

[Mark Adams]

>
>
> No joke, Amneet found that PCASM with lots of small subdomains was
> spending a ton of time in view calls.
>
>
> (And, of course, Barry fixed it by adding this configure flag --- thanks
> Barry!)
>
> Note that it does not matter whether you *use* view or not.
>

Oh wow. So no view with ASM,

Garth, you will need to configure with '--with-viewfromoptions=0'


>
> -- Boyce
>
>
> -- Boyce
>
> I guess we should have a flag or not iterate over the blocks in ASMView ...
>
>
>>
>> -- Boyce
>>
>>
>>   Barry
>>
>> On Jun 22, 2016, at 7:51 AM, Mark Adams <mfadams at lbl.gov> wrote:
>>
>> I'm trying to get block smoothers to work for gamg.  We (Garth) tried
>> this and got this error:
>>
>>
>> - Another option is use '-pc_gamg_use_agg_gasm true' and use
>> '-mg_levels_pc_type gasm'.
>>
>>
>> Running in parallel, I get
>>
>>     ** Max-trans not allowed because matrix is distributed
>> ----
>>
>> First, what is the difference between asm and gasm?
>>
>> Second, I need to fix this to get block smoothers. This used to work.
>> Did we lose the capability to have blocks that span processor subdomains?
>>
>> gamg only aggregates across processor subdomains within one layer, so
>> maybe I could use one layer of overlap in some way?
>>
>> Thanks,
>> Mark
>>
>>
>>
>
>
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