Dear all, I'm implementing a Runge-Kutta scheme where inside each time step I have to solve three linear systems with the same matrix but different right hand sides. I'm using the ShellMatrix concept since the matrix is of the type
A = B + v*w^T where B is sparse. Also, the matrix seems to be quite ill-conditioned, which is why I use a sparse direct solver (that is, SuperLU_Dist) on B as a preconditioner inside a GMRES scheme for A. Setting up the preconditioner of course takes quite a long time; once this is done, everything else is fast since GMRES converges in less than 10 steps. The only problem is that the preconditioner is set up in each of the three solves which makes everything essentially by a factor of three slower than necessary. I see that there is now a Preconditioner class in libMesh that has not been there in earlier times. Is that in a usable state? Can it reuse a precoditioner between successive solves without setting it up again? Is there any tutorial about how to use it? Best Regards, Tim -- Dr. Tim Kroeger [email protected] Phone +49-421-218-7710 [email protected] Fax +49-421-218-4236 Fraunhofer MEVIS, Institute for Medical Image Computing Universitaetsallee 29, 28359 Bremen, Germany ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
