On Tue, Feb 19, 2008 at 09:18:54AM +0100, Johan Hoffman wrote: > > On Mon, Feb 18, 2008 at 04:35:54PM +0100, Johan Hoffman wrote: > >> > This is good juncture at which re-focus on important goals for a > >> hopefully not too distant next release. Three priorities that I see are: > >> > > >> > - New build system. > >> > > >> > - Improved support for parallel assembly and solve. The class Function > >> will probably need the most work. Good goals would be to get Poisson and > >> elasticity demos running in parallel. > >> > >> I thought the Poisson problem was running, and showing good parallel > >> scaling? Or maybe that was a test outside the dolfin-dev demos? > > > > The demo is in src/demo/fem/assembly/. > > Ok, so the matrix assembly is working and is implemented as a demo, but > solve is missing.
Two things are missing: solve and handling forms with coefficients in parallel (the Vector in DiscreteFunction holding the dofs should be parallel). Garth has done parallel solve (with PETSc) in src/sandbox/passembly/main.cpp so it shouldn't be much work to get the solve part going. > >> We (Nicklas) have now a preliminary distributed parallel implementation > >> running for Poisson and a Unicorn flow solver. The structure is still > >> quite messy and the partitioning is based on Metis, but we expect it to > >> be > >> integrated with DOLFIN in the coming months, hopefully before the > >> summer. > > > > Could this be done in small pieces? I'm a little worried about seeing > > big changesets that add things to the mesh classes. > > Yes, we need to figure out how this should be done to best fit with the > existing mesh classes. When we have cleaned up the code we will take that > discussion here at the dolfin mailing list so that we can agree on a > solution. Excellent. > >> When the structure is more clear we can discuss on the mailing list how > >> to > >> best incorporate this into DOLFIN. Apart from the structure of the > >> implementation we are also focusing on distributed local mesh > >> refinement. > > > > Great. > > > > What is the difference from what we have now? Is it the same but with > > a distributed mesh (so each processor just sees the local part, not > > the whole mesh)? Or is it something different? > > I think the main issues are to handle refinement over > partition-boundaries, and efficient re-partitioning after refinement (for > load-balancing). ok, we haven't considered this at all. > > I think what we have now can be fairly easily extended to a > > distributed mesh without any (significant) changes to the mesh > > classes. The key point is to build the DofMap in parallel. Take a look > > here, in particular Section 6 and Algorithm 5: > > > > http://simula.no/research/scientific/publications/Simula.SC.75 > > > > Seems I need a username/password for this. Sorry, try here: http://home.simula.no/~logg/tmp/ -- Anders > /Johan > > >> > - Testing of QuadratureFunction and adding corresponding demos. > >> > > >> > Another point is to add Trilinos as a supported linear algebra back > >> end. > >> How does this tie up with closer links to PyCC? > >> > > >> > Garth > >> > >> - Something else that I think is important is to include geometry in > >> DOLFIN. We were to start such a project before Christmas, but we lost > >> the > >> msc student that was supposed to work on this. I would expect that we > >> restart this later this spring. Basically we need to import CAD-geometry > >> (or other geometry descriptions), create an internal DOLFIN format > >> (typically based on NURBS or similar) with a Geometry-class. Typical > >> functionality needed is then to project a point onto the surface > >> geometry. > > > > That would be nice. > > > > > > > >> /Johan > >> > >> > >> > _______________________________________________ > >> > DOLFIN-dev mailing list > >> > [email protected] > >> > http://www.fenics.org/mailman/listinfo/dolfin-dev > >> > > >> > >> > >> > >> > >> _______________________________________________ > >> DOLFIN-dev mailing list > >> [email protected] > >> http://www.fenics.org/mailman/listinfo/dolfin-dev > > _______________________________________________ > > DOLFIN-dev mailing list > > [email protected] > > http://www.fenics.org/mailman/listinfo/dolfin-dev > > > > > _______________________________________________ > DOLFIN-dev mailing list > [email protected] > http://www.fenics.org/mailman/listinfo/dolfin-dev _______________________________________________ DOLFIN-dev mailing list [email protected] http://www.fenics.org/mailman/listinfo/dolfin-dev
