New block ILU preconditioner scheme for numerical analysis of very large electromagnetic problems

Large electromagnetic scattering and radiation problems are tackled by iterative solvers, which require the use of huge preconditioners. Most often, the incomplete LU decomposition (ILU) of the preconditioner is applied to the system matrix at each iteration. However, the preconditioner ILU cannot be done in-core when the size of the preconditioning matrix exceeds the available memory. This paper presents a new preconditioning scheme to do the preconditioner ILU in small blocks that fit in core memory. The resulting approach allows the solution of very large problems in small computers.