On Wed, Aug 24, 2011 at 08:43:40AM -0400, Garth N. Wells wrote: > > > On 24/08/11 08:07, Anders Logg wrote: > > On Wed, Aug 24, 2011 at 07:22:53AM -0400, Garth N. Wells wrote: > >> > >> > >> On 24/08/11 03:50, Anders Logg wrote: > >>> What is the plan for XMLLocalMeshData (using the DOM interface) vs > >>> XMLLocalMeshDataDistributed (using the SAX interface)? > >>> > >> > >> Both for the time being. > >> > >>> Reading boundary indicators is currently failing with > >>> > >>> RuntimeError: *** Error: Inconsistent state in XML reader: 6. > >>> > >>> Should this be fixed in XMLLocalMeshDataDistributed or is the plan to > >>> replace it with XMLLocalMeshData? > >>> > >> > >> In XMLLocalMeshDataDistributed. > > > > Could you elaborate? The functionality for reading and distributing > > boundary markers (in parallel) is currently broken and we want to fix > > it. But we need to know more about the design. I don't want to fix > > something if you decide to break it 5 min later. > > > > It never 'properly' worked in parallel. There were some messy ad hoc > changes made on top of functions that were planned for overhaul. I made > clear before this that parallel functionality was being sorted out (it's > not just in io, but also partitioning, etc), so the fact that it's not > working now should not be a surprise.
It came as a surprise since there was a unit test for it and the unit test was removed. But nevermind, the important thing now is to get it working again. > There is a lot of missing functionality is parallel, so patience is > required to get things done properly. > > > Should we continue to use libxml2? Why not use the DOM parsing all the > > way? > > > > Because I'm inclined to keep SAX parsing for meshes since meshes are the > most likely to be created externally, and need to be scalable for > reading. Other objects (e.g., vectors) are likely to be created and > written by DOLFIN, so will eventually use parallel HDF5 for scalable > parallel io. The reason I once chose to implement the XML parsing using SAX, and why Ola decided to use SAX in his rewrite 2 years back, is exactly that: scalability and efficiency. I don't see why it should be different for meshes than any other objects. Other objects can also be large. It seems messy to use both. > > What is the difference between XMLLocalMeshData and > > XMLLocalMeshDataDistributed etc. > > > > Initially I planned to use DOM for all, but as outlined above decided > after some testing to retain SAX for meshes (but update to SAX2, since > the libxml2 SAX parser is deprecated and has memory leaks). Hence, > XMLLocalMeshData uses DOM and XMLLocalMeshDataDistributed uses SAX. So > far I've kept the DOM version since it's easy to code and could be > useful when reading non-distributed meshes on each process (which may > differ on different processes). I don't understand the difference between XMLLocalMeshData and XMLLocalMeshDataDistributed. Is XMLLocalMeshDataDistributed doing now what XMLLocalMeshData did before? -- Anders _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : dolfin@lists.launchpad.net Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
