dolfin team mailing list archive

["Ola Skavhaug" <skavhaug@xxxxxxxxx>]

On Wed, Aug 13, 2008 at 2:57 PM, Johan Hoffman <jhoffman@xxxxxxxxxx> wrote:

> >
> >
> > Johan Hoffman wrote:
> >>>
> >>> Anders Logg wrote:
> >>>> On Tue, Jun 17, 2008 at 02:45:41PM +0100, Garth N. Wells wrote:
> >>>>> It would be useful to lay out a plan for tackling DofMaps. Getting
> >>>>> this
> >>>>> right is the key to parallel assembly, assembly optimisations and
> >>>>> applying Dirichlet boundary conditions by eliminating Dirichlet dofs
> >>>>> from the global system.
> >>>>>
> >>>>> I'm happy to take a look, but I'll need some time because I've lost
> >>>>> my
> >>>>> overview of DofMaps. If someone else is already on top of it, I'd be
> >>>>> happy to provide feedback.
> >>>>>
> >>>>> Garth
> >>>> I won't have time to look at it until after the summer and I haven't
> >>>> started.
> >>>>
> >>>> Anyway, I think we should wait until after the next release until we
> >>>> start messing with the dof maps.
> >>>>
> >>>> Are there any issues we need to sort out before releasing 0.8? I'm
> >>>> thinking about a new release some time this or next week.
> >>>>
> >>>> One is to fix the bug in DirichletBC, but other than that?
> >>>>
> >>> Now would be a good time for a release so I can start messing with
> >>> DofMaps.
> >>>
> >>> Garth
> >>
> >> Has anything more been done about the DofMap design? During the summer
> >> Niclas has extended to general elements his adaptive algorithm for
> >> distributed parallel computing, so we are now ready to start messing
> >> with
> >> the DofMaps in order to implement his algorithm in DOLFIN.
> >>
> >
> > It has been given some thought, but no changes have been made in the
> > code yet.
>
> Ok. Any threads on the list to point to where this is discussed?
>
> If you have something already, I would suggest making it
> > publicly available somewhere for feedback before starting work on DOLFIN.
>
> It is a refinement and generalization of the thesis work of Niclas Jansson
> which was discussed on the list before the summer. Is is outlined in his
> report:
>
> http://www.nada.kth.se/utbildning/grukth/exjobb/rapportlistor/2008/rapporter08/jansson_niclas_08051.pdf
>
> My announcement here was to initiate a discussion of the detailed
> implementation, and to check if other DOLFIN-people were working on
> similar stuff to avoid double/conflicting development.
>
> /Johan
>

Very good. We were about to start on this task, so now a good point in time
to join forces.
As a starting point, it would be nice to agreeing on what data is needed in
addition to the partitioned meshes to construct the global dofmap. I.e.
which MeshFunctions to construct during the mesh paritioning process. Are
you people using the same {T,S,F} input as Anders describes in Algorithm 5
in his paper?


Ola


>
> >
> > Garth
> >
> >
> >> I see Anders report referenced in the code, where the mapping scheme
> >> described is fairly close to what Niclas has implemented, although there
> >> are some differences. We will sit down today to sum up what we think
> >> needs
> >> to be done, and then we can discuss this on the mailing list.
> >>
> >> /Johan
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
> >
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> >
>
>
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-- 
Ola Skavhaug