On Fri, Sep 19, 2014 at 3:36 AM, Eduardo Hernandez < [email protected]> wrote:
> > Dear All, > > I recently installed libMesh and I am trying things out; I am new to > libMesh and also to FE methods, so I apologise if this is a rather basic > question, but your help would be much appreciated. Based on the example > codes provided, I have written a little program to solve a 1D eigenvalue > problem which works fine. In my first implementation I used LAGRANGE finite > elements, which I understand guarantee continuity of the (eigen)functions > across elements, but not of their derivatives (C0 continuity). I also > understand that in order to enforce continuity of the 1st derivative I > should switch to finite elements based on Hermite interpolating > polynomials, which I have done with the following lines of code: > > MeshTools::Generation::build_line( mesh, npoints, -L0, L0, EDGE3 ); > … > eigen_system.add_variable( "p", THIRD, HERMITE ); > > and if I am not mistaken, this will ensure that the eigenvectors have C1 > continuity (though please correct me if wrong). My question is: is it > possible to enforce C2 continuity (continuity of function, first and second > derivatives)? I naively assumed that this would be possible by using a > higher order of HERMITE (e.g. FIFTH) in the appropriate line above, but > this does not appear to work. > C2 would be very unusual...as far as I know there are no C2 elements in libmesh. Are you solving a problem with 6th-order derivatives or something? -- John ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that Matters. http://pubads.g.doubleclick.net/gampad/clk?id=160591471&iu=/4140/ostg.clktrk _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
