Convergence behaviour of deflated GMRES(m) algorithms on AP3000

gmres(m) method, the restarted version of the gmres (general-ized minimal residual) method, is one of the major iterative methods for numerically solving large and sparse nonsymmetric problems of the form Ax = b. However, the information of some eigenvectors that compose the approximation disappears and then the good ap-proximate solution cannot be obtained, because of this restart. Re-cently, in order to improve such a weak point, some algorithms whic