“…Limited Memory Preconditioners (LMPs) are based on the idea of improving a first-level preconditioner, henceforth referred to as seed precon-ditioner, with a technique inspired by limited-memory quasi-Newton methods [15]. Initially developed for symmetric positive definite matrices [10,11], LMPs have been extended to saddle-point and to general indefinite matrices, and have been used in different applications, either to improve a preconditioner for a single system or to obtain preconditioners for sequences of linear systems with fixed or varying matrices [2,4,16].…”