ABSTRACT This paper discusses discusses the preconditioner for solving the linear system Ax = b, where A is of the form M-matrix, which is a review of the Zhuan-De Wang and Ting-Zhu Huang paper [Applied Mathematics Letters, 19 : 1029 − 1036 (2006)]. Numerical experiments using some sizes of A show that the convergence rate of Jacobi and Gauss-Seidel type methods can be increased using t…