On Mon, 3 Dec 2007 09:53:23 +0100 (MET) "Johan Hoffman" <[EMAIL PROTECTED]> wrote:
> > 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 ([email protected]) 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 > It's a different strategy that uses point to point instead of collective communication. However the plan for parallel assembly should be more or less the same. I attached the more detailed TODO list, it should explain the necessary changes to the Mesh classes. Niclas
todo
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