Evaluation Index of Acceleration Factor and Ordering in Shifted ICCG Method for Electromagnetic Field Analyses

This paper introduces a simple way to evaluate the preconditioning effect in the shifted ICCG method. The proposed evaluation index is easily calculated with little additional memory in an incomplete factorization process; thus, it can be used for setting appropriate parameters for the solver, such as an acceleration factor and the ordering of unknowns, prior to the time-consuming iteration process. Numerical results show that the evaluation index gives the good estimate of the number of iterations necessary for convergence