  In the recent paper [Duff I. et al, SIAM J. Sci. Comp., 37(3) (2015),
A1248-A1269] the authors proposed an interesting procedure for the parallel
solution of large, sparse consistent linear systems of equations. In this
respect, according to a reordering of the initial matrix, the authors extend it
by obtaining mutually orthogonal row blocks, which give them the possibility to
get a solution through only one Block Cimmino iteration. We present in our
paper an extension of this procedur to inconsistent large sparse linear least
squares problems. Through this extension applications of the method are well
suited for problems arising in Compressed Sensing, Image Reconstruction in
Computerized Tomography and Rigid Body Dynamics.
