For what it's worth, as a user I always found the mere existence of yet another mesh file format confusing. XDMF supports lossless I/O for meshes, so naturally I'm in favor of this approach. (Not sure how well mesh generators support XDMF, but there certainly is a chance for better support than the custom XML format.)
--Nico On Fri, Jan 3, 2014 at 7:27 PM, Garth N. Wells <[email protected]> wrote: > The handling of XML IO in parallel in DOLFIN is presently inconsistent and > extremely slow for large files. Moreover, the code is clumsy. Now that we > have proper parallel IO support via HDF5 (and XDMF) and MPI-IO, I would like > to propose that XML IO be simplified to be serial only. Only XML meshes are > presently read in a memory scalable fashion. To read meshes in parallel, > supporting the below two implementations is suggested: > > 1. Recommended approach: Use XDMF/HDF5 format. To convert existing meshes: > - (simple) If mesh fits into memory, read XML mesh into DOLFIN and use > DOLFIN to write XDMF file. > - (general) Use new dolfin-xml-to-hdf5 Python script to convert XML files > to XDMF/HDF5. Script uses SAX XML parser, so memory limitations are not a > problem for large meshes. > > 2. Supported approach: DOLFIN reads XML mesh file on one process only and > distributes mesh to all processes. This will be considerably faster than the > present parallel implementation, which uses a slow SAX parser, but it is > limited to problems for which the mesh fits into memory on a process. > > Most users will require no code changes but will see a speed-up. For large > XML files that don’t into memory on one process, HDF5/XDMF should really be > used because it is orders of magnitude faster for large problems. The > proposed change means that the XML SAX parser can be removed and libxml will > no longer be a DOLFIN dependency. > > Any objections? > > Garth > _______________________________________________ > fenics mailing list > [email protected] > http://fenicsproject.org/mailman/listinfo/fenics _______________________________________________ fenics mailing list [email protected] http://fenicsproject.org/mailman/listinfo/fenics
