Hi,
Experimenting FE convergence abilities when solving ODEs, I am facing an interesting case with Lagrange elements. The error computed with the analytical solution is growing up when the number of elements exceed approximatively 80. Then, the node values are dramatically falling. However, this only occurs when quadratic (Edge3) and cubic (Edge4) shape functions are used. Using linear Lagrange (Edge2) or cubic Hermite (Edge3) verify the stability of the error when incrementing the number of elements (To one thousand or more). The problem seems also independent from the equation's coefficients. Thinking of an interaction between Petsc and Laspack, I tried a compilation with the "--disable-laspack" option but nothing changed. Any suggests are welcome, Maxime NB: To implement the Neumann condition in a transient case, I finally used, on the boundary, a finite difference approximation. ------------------------------------------------------------------------- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
