Dear all, I am currently working on some large soil-structure interaction problems and therefor I have a finite element discretization that is going be solved in the frequency domain. This results in a symmetric, but indefinite matrix. I have not been able to find a proper method to use when solving it with PETSc.
I was wondering if you guys have any recommendation on what to try, both concerning method but especially the PC? Is it recommended to use a composite PC for indefinite problems? I have tried the methods (such as MINRES, SYMMLQ) that are suggested for indefinite problems with no success. For small problems, GMRES+ASM+LU works fine, but for larger the memory consumption goes off the chart. I've also been able to use MUMPS but find it both memory and time consuming. I apologize for my lack of knowledge about iterative methods, Best regards, M?rten
