On Mon, 22 Mar 2010, Liang wrote:
> Sounds a difficult work. I have a question on the quadrature rule of > integration, doesn't the libmesh use the unified gauss-legendre quadrature > for all elements? I knew some FEA packages use the gauss-legendre for any > element, or it is a different concept between the macroelement and the single > element? Gauss-Legendre rules of high enough order give exact results for polynomial non-macroelements, but on a macroelement the reduced smoothness between subelements hurts you. The easiest (albeit not the most efficient) solution for piecewise-polynomial macroelements is to just combine a (translated and reweighted) Gauss rule on each subelement. libMesh has a bunch of non-Gauss-Legendre rules for general elements available too; some for verification and underintegration, some just because there are multiple ways to do quadrature in 2D/3D with different tradeoffs. Check the source code first if you're curious; John has most of it pretty well documented. --- Roy ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
