0 Conclusions

We have implemented a software package for constructing and solving the sparse coefficient matrix linear systems arising from solving partial differential equations based on unstructured grids. The sparse symmetric complex linear system can be solved by either a precondi-tioned bi-conjugate gradient solver, or by a two-stage Cholesky factorization solver, or by a hybrid solver combining both. The interface of the solver is designed so that one interface fits to all three different solvers. Scaling test runs for fixed problem-size/processor indicate good scaling behavior of the two-stage hybrid method.