From: Nasser Mohieddin Abukhdeir <nasser.abukhdeir@mc...>  20080829 05:50:28

Hello: I have a nonlinear timedependent PDE system where the individual variables compose a second order tensor. This form is convenient for simulation, but not for interpreting the data, for which I need the eigenvalues and vectors of the tensor. I don't really have the choice of using Octave to do this postsimulation in that I am using adaptive meshing and a huge dataset that requires parallelization. I'm trying to figure out a sensible way to modify my Libmesh implementation (using FEMSystem) to do this but I'm not sure how to proceed. Is there a way to tell Libmesh that certain variables are neither timeevolving or constraints, so that they are not accounted for in the factorization? So I would start with a FEMsystem with all of the tensor components, eigenvalues, and eigenvector components in the same system. Would I then just implement the postprocessing functions and use the Gnu Scientific Library to compute the eigenvalues/vectors based upon the tensor components computed from the current solution. Please give me a few pointers...  Nasser Mohieddin Abukhdeir Graduate Student (Materials Modeling Research Group) McGill University  Department of Chemical Engineering http://webpages.mcgill.ca/students/nabukh/web/ http://mmrg.chemeng.mcgill.ca/ 