Complete pivoting strategy for the left-looking Robust Incomplete Factorization preconditioner

In this paper, we have used a complete pivoting strategy to compute the left-looking version of RIFRIF preconditioner. This pivoting is based on the complete pivoting strategy of the IJKIJK version of Gaussian Elimination process. There is a parameter αα to control the pivoting process. To study the effect of αα on the quality of the left-looking version of RIFRIF preconditioner with complete pivoting strategy, we have used ten different values of this parameter. In the numerical experiments section, the quality of the left-looking version of RIFRIF preconditioner with complete pivoting strategy has been compared to the quality of the right-looking version of this preconditioner.