关键词: 非对称线性方程组, Krylov子空间方法, 最小联合向后扰动, IMinpert算法, 右预处理技术, 不完全正交化过程

Abstract: The truncated version of the Minpert method—the IMinpert algorithm for large unsymmetric linear systems has been given in another paper. In order to accelerate the convergence rate of the IMinpert algorithm, the right preconditioning technique is used, and then the Flexible IMinpert algorithm（FIMinpert algorithm） is presented in this paper. The theoretical deduction and practical implementation issues of the FIMinpert algorithm are discussed in details. Numerical experiments show that the FIMinpert algorithm can achieve better convergence rate than the IMinpert algorithm and the GMRES algorithm.

Key words: unsymmetric linear systems, Krylov subspace methods, minimum joint backward perturbation, IMinpert algorithm, right preconditioning technique, incomplete orthogonalization process