Hi, I CCed to our hpfem list, so that people in our group can have a look at this too.
On Mon, Mar 2, 2009 at 5:35 PM, Roy Stogner <[email protected]> wrote: > > > On Mon, 2 Mar 2009, Ondrej Certik wrote: > >> On Mon, Mar 2, 2009 at 12:16 PM, Roy Stogner <[email protected]> >> wrote: >>> >>> >>> On Mon, 2 Mar 2009, Ondrej Certik wrote: >>> >>>> If I find time, I'd like to create Python interface to libmesh, >>>> because I used it in the past and I would like to compare libmesh >>>> h-adaptivity with our hp-adaptivity. >>> >>> If you're already doing that, you might want to go one step farther >>> and compare libmesh hp-adaptivity with yours. The former is >>> theoretically working but I've rarely gotten the convergence rates I >>> expected out of it, so I suspect there's some subtle bugs left. >> >> Ah, yes, absolutely! I didn't know that libmesh also has >> hp-adaptivity. > > Well, that might be overstating the case. ;-) libMesh has the > ability to adaptively refine p-hierarchic element types in h and/or p, > which technically might qualify as "has (isotropic) hp-adaptivity"... > but libMesh lacks a good heuristic for deciding which type of > adaptation to do. IIRC the only strategy classes I wrote were "h > adapt if you touch a prespecified singularity, p adapt otherwise" and > "try to see whether an h-coarsening or a p-coarsening would be worse, > then h-adapt or p-adapt respectively instead". The former seemed to > give exponential but probably non-optimal convergence in a couple > benchmark problems; the latter didn't even go exponential. > >> Then I will definitely give it a shot. > > Thanks! I would have liked to spend more time on this myself, but > eventually dissertation work took precedence. > > For that matter, I'd love to have an excuse to play with it now, but I > still haven't figured out how to make Ben's hypersonics formulations > work perfectly with hierarchic elements. That's awesome that you are interested in this. At this moment, I am quite busy with other things, but I am very interested in this comparison. Does the isotropic hp-adaptivity work in 3d? The difficult part is in choosing the right candidate for hp-adaptivity, and I know that the guys in my group spent months in getting it right, so I am curious in comparing it with your version to see if it's different. I want to see the graph, then I will believe. :) On Sun, Mar 1, 2009 at 3:30 PM, Kirk, Benjamin (JSC-EG311) <[email protected]> wrote: > is that these tend to be more "industrial-type" applications, where > higher-order elements are often not used for various reasons (non-smooth > solutions, sharp complex geometry, etc...) In fact, hp-fem performs the best exactly with solutions that are both non-smooth and sharp somewhere (it uses a low polynomial order there) and very smooth somewhere else in the domain (it uses a high polynomial order there). But as I said, it's tough to get everything into a production ready state, but it's exciting when we get there finally both in 2D and in 3D. Ondrej ------------------------------------------------------------------------------ Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise -Strategies to boost innovation and cut costs with open source participation -Receive a $600 discount off the registration fee with the source code: SFAD http://p.sf.net/sfu/XcvMzF8H _______________________________________________ Libmesh-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-devel
