From: Tim Kroeger <tim.kroeger@ce...>  20081030 15:45:13

Dear libMesh team, It seems as if the thing is now running quite well for me. (I fixed some bugs in the meantime, all of which were all on the application side.) I've still not been able to test it in parallel though, since the cluster is still making trouble. I hope this will be repaired soon (altough I've been hoping this since several weeks now). There is one weakness of my implementation: If you have A = B + v*w' (as I have) and want to use B as the preconditioning matrix (to be able to use ILU) (as I am doing now), you have to store two sparse matrices although there is only one. That is because LinearImplicitSystem::solve() calls have_matrix("Preconditioner") to find out whether the preconditioning matrix differs from the system matrix. So I have to add a preconditioning matrix manually. On the other hand, LinearImplicitSystem::matrix exists nevertheless. I think I don't have to put too much effort now in solving this problem since you will restructure the implementation anyway and your restructuring is likely to resolve this problem "on the fly". Another issue is a sensible example program that uses the shell matrix concept. I think it should be sensible to have one since there are some pitfalls (such as the correct constraining methods I mentioned last week). Unfortunately, I cannot think of a sensible, simple example application. (The one I'm working on is far too complicated for that purpose.) Does anyone have a sensible idea? Best Regards, Tim  Dr. Tim Kroeger Phone +494212187710 tim.kroeger@..., tim.kroeger@... Fax +494212184236 MeVis Research GmbH, Universitaetsallee 29, 28359 Bremen, Germany Amtsgericht Bremen HRB 16222 Geschaeftsfuehrer: Prof. Dr. H.O. Peitgen 