2011/4/26 Alejandro Marcos Arag?n <alejandro.aragon at gmail.com> > Hi Jed, thanks for replying. In fact, the problem I sent the results from > is a dynamic problem of a simply supported beam subjected to a constant load > at the center, so I'm integrating in time. >
I take it there is no buckling. > The material is linear elastic so the stiffness matrix doesn't change in > non-zero structure. Of course the right hand side changes, but I don't think > this is the problem because at some point it takes it goes back to just a > few iterations to solve. The behavior is cyclic, but I don't understand the > reason for this. I've noticed the same behavior of the solver also in > quasi-static problems (increasing the load gradually but not integrating > over time). > Is the convergence relatively smooth? Are you losing a lot in GMRES restarts (every 30 iterations)? If you have a symmetric formulation (including boundary conditions), you can use -ksp_type cg, otherwise try -ksp_gmres_restart 500. Also, try solving the system with a random right hand side. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20110426/28e15076/attachment.htm>
