A note on two block-SOR methods for sparse least squares problems
Robert M. Freund · Linear Algebra and its Applications · 1987
We compare two recently proposed block-SOR methods for the solution of large least squares problems with the conjugate gradient algorithm for solving the specially preconditioned normal equations. By proving that all three methods are based on the same Krylov sequence, we show that the conjugate gradient algorithm is generally preferable to the two SOR approaches.