Re: [Libmesh-users] Variable groups to use blocked matrix (*BAIJ)

[David K. <dav...@ak...>]

On Thu, May 10, 2018 at 9:38 AM, Roy Stogner <roy...@ic...>
wrote:

>
> On Wed, 9 May 2018, John Peterson wrote:
>
> On Wed, May 9, 2018 at 11:56 AM, Linda G <li...@na...> wrote:
>>
>> Dear Libmesh Users,
>>>
>>> We are trying to figure out how to set up a Stabilized NS FEM formulation
>>> to work
>>> in a blocked matrix fashion. After reading the documentation we realized
>>> that this boils down to define a
>>> variable group, but we could not find any example (even the Elasticity
>>> ones) that uses the
>>> block matrix (*BAIJ) feature.
>>> Please remember that our formulation is stabilized, so we are using P1P1
>>> and P2P2 for velocity and pressure.
>>> Is the function to define variables groups a member of System class or
>>> DofMap class?
>>> Please if anyone has a working example, or teach us how to do it, we
>>> really
>>> appreciate.
>>>
>>>
>> If I understand correctly, this should happen automatically if you have a
>> System with 1 variable group that contains more than 1 var, provided that
>> you configure libmesh with --enable-blocked-storage. The default is
>> --disable-blocked-storage since I believe we ran into some issues while
>> using this option in the past.
>>
>
> https://github.com/libMesh/libmesh/issues/703 is the only concrete
> issue I can find, thanks to SourceForge mailing list changes breaking
> old archive links.
>
> We should probably track this down soon so we can at least upgrade
> blocked-storage from "enable only explicitly" to "enable with
> --enable-everything".  I haven't been testing --enable-blocked-storage
> for a long time so it may have regressed even further.
> ---
> Roy



Should we re-open #703 then? I agree that we never got to the bottom of
what was going on there, we just avoided the issue by disabling some
examples.

David