dolfin team mailing list archive

["Johan Hoffman" <jhoffman@xxxxxxxxxx>]

> On Sun, Dec 02, 2007 at 06:17:35PM +0100, Johan Hoffman wrote:
>> >
>> >
>> > Johan Hoffman wrote:
>> >>> Johan Hoffman wrote:
>> >>>> Hi all,
>> >>>>
>> >>>> Connected to this discussion is also the msc thesis work on dolfin
>> >>>> parallization of Nicklas Jansson at KTH. He has now started working
>> on
>> >>>> this based on the updated TODO list of dolfin. He has tried to send
>> an
>> >>>> email to this list (dolfin-dev@xxxxxxxxxx) but it appears that it
>> is
>> >>>> stuck
>> >>>> in a filter awaiting moderator approval.
>> >>> If he joins the list, he'll be able to make posts.
>> >>
>> >> Ok.
>> >>
>> >>> Maybe someone (a moderator) could
>> >>>> help out so that we can get past this, to better coordinate
>> >>>> parallelization efforts?
>> >>>>
>> >>> One point on the TODO list: we discussed some time ago the mesh
>> >>> partitioning, and decided against ParMETIS or METIS because they do
>> not
>> >>> use a GPL (compatible) license. Magnus has implemented a nice
>> >>> partitioning interface which uses SOCTCH which does have a GPL
>> >>> compatible license.
>> >>
>> >> Ok. Does the switch to LGPL licence for dolfin make any difference?
>> Or
>> >> is
>> >> it still a conflict?
>> >>
>> >
>> > There is still a conflict. The METIS license basically says that it
>> can
>> > be used for non-profit purposes only, and permission is required to
>> > re-distribute it.
>>
>> Ok, then there is a problem.
>>
>> >> About Scotch; the argument was that it lacked parallel partitioning,
>> and
>> >> a
>> >> few other nice features of parMetis. But it seems that Scotch v5.0 is
>> >> moving towards a parallel implementation as well?
>> >>
>> >
>> > It does have it now. That said, I can't see us using or needing
>> parallel
>> > partitioning in the short- to medium-term future.
>>
>> Ok. Maybe we'll manage with Scotch for now then.
>>
>> As for parallel assembly, we will need this in the coming months, so we
>> will push the fully parallel approach within Nicklas' msc project,
>> including parallel redistribution for adaptively refined meshes (which
>> parMetis seems to support nicely).
>>
>> /Johan
>
> Sounds very good, but if major changes to the Mesh classes are
> necessary (which seems likely), I suspect I will be somewhat sensitive
> to having all those changes pushed at once. So it would be good to
> discuss plans for the design as early as possible so we can all feel
> comfortable with the changes.
>
> --
> Anders

I agree. That's why the TODO list was added in the dolfin rep, and an
accompanying dolfin-dev post was sent (...which got stuck in the filter).
With a fresh dolfin-dev membership, Nicklas can resend his post where the
strategy is presented in more detail, which then anyone can comment on.

I would expect the plan to be rather uncontroversial, and it will fit
nicely with the work of Magnus.

/Johan

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