Abstract
In this paper, we consider "Cutting-off" again preconditioning matrices made by the preconditioner of an earlier literature and verify the influence and validity of our method. In this earlier literature, a preconditioner using complete factorization of the matrix LDL^T=A_c obtained from drop-thresholding of the original coefficient matrix A is proposed as suitable methods for matrices which have many nonzero elements and complex nonzero structure. We explain the earlier literature and our method, and report the performance of our method for the sparse matrices that arise from our application including comparison with earlier literature.
