> On Feb 6, 2015, at 9:29 PM, Jed Brown <j...@jedbrown.org> wrote: > > Manav Bhatia <bhatiama...@gmail.com> writes: > >> I am in agreement with that. However my situation is more rudimentary than >> that. >> >> If I run the same problem in ABAQUS, it uses a multifraontal direct solver >> and gets done in two minutes. >> >> If I use the -ksp_type preonly -pc_type lu on my code built on libmesh and >> petsc, it takes ~16GB in storage and half hour for solution. > > Do you have the same matrix in both cases? Direct solvers compute an > ordering (e.g., by nested dissection), so changing the ordering of your > matrices is not likely to change much. What direct solver is ABAQUS > calling?
All that I could find in its manuals is that it uses a multifront technique (http://www.maths.cam.ac.uk/computing/software/abaqus_docs/docs/v6.12/books/usb/default.htm?startat=pt03ch06s01aus46.html#usb-anl-asolveroverview). I am not sure if I understand your point. Are you saying that using a fill-reducing ordering for the dofs would not change the performance of a direct solver? -Manav ------------------------------------------------------------------------------ Dive into the World of Parallel Programming. The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
