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## libmesh-users

 [Libmesh-users] 2nd order mixed derivative From: - 2007-03-31 02:59:08 ```Hi, I have a simple 2D equation with the following form: Uxx+Uyy+Uxy=0 Uxx, Uyy are the 2nd partial derivative and Uxy is the mixed 2nd artial derivative. Since I'm not a math major, I'm having trouble setting up the weak formulation due to the mixed derivative term. Thus I don't know how to implement it with libMesh. Any help will be greatly appreciated. -DX ```
 [Libmesh-users] 2nd order mixed derivative From: Dong Xu - 2007-03-31 07:26:36 ```Hi, I have a simple 2D equation with the following form: Uxx+Uyy+Uxy=3D0 Uxx, Uyy are the 2nd partial derivative and Uxy is the mixed 2nd artial der= ivative. Since I'm not a math major, I'm having trouble setting up the weak formulat= ion due to the mixed derivative term. Thus I don't know how to implement = it with libMesh. Any help will be greatly appreciated. -DX ```
 Re: [Libmesh-users] 2nd order mixed derivative From: Roy Stogner - 2007-03-31 03:51:27 ```Sourceforge really needs to get its list servers upgraded. This question and about five answers appear to have made it through the deal.II mailing lists before the question alone got to ours. The weak forms you were given by the deal developers look correct - take a look at ex13 to see how similarly complex derivative terms are coded in libMesh, then send us another email if you still need more help. --- Roy On Fri, 30 Mar 2007, dxu@... wrote: > Hi, > > I have a simple 2D equation with the following form: > > Uxx+Uyy+Uxy=0 > > Uxx, Uyy are the 2nd partial derivative and Uxy is the mixed 2nd > artial derivative. > > Since I'm not a math major, I'm having trouble setting up the weak > formulation due to the mixed derivative term. Thus I don't know how to > implement it with libMesh. > > Any help will be greatly appreciated. > > -DX > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > Libmesh-users mailing list > Libmesh-users@... > https://lists.sourceforge.net/lists/listinfo/libmesh-users > ```