“…where m m A R × ∈ is a symmetric positive definite matrix, and m n B R × ∈ is a matrix of full column rank. The augmented system like (1) appears in many different applications of scientific computing, such as the finite element approximation to solve the Navier-Stokes equation [1,2], the constrained least squares problems and generalized least squares problems [3,4,5,6,7,8] and constrained optimization [9].…”