Abstract
Diagonally relaxed RIC factorization which revises relaxation on amount of modification for diagonal entries to improve convergence rate is effective preconditioning for CG method for solving linear system of equations with symmetric positive definite coefficient matrix. This preconditioning, however, demands much memory due to fill-in appeared during factorization. In this paper, we verify performance of RIC(0) factorization with no fill-in and modified RIC(0) factorization using acceleration parameter. Numerical experiments show that the proposed modification is extremely effective for gaining high convergence rate of the CG method.
