Matlab, Algorithms, Eigenvalue, Singular Values, Computation.
Make our test matrix rectangular by inserting a couple of rows of the identity matrix. I = eye(8,8); A = [A(1:4,:); I(1,:); A(5:8,:); I(2,:)] Use a Householder operating from the left to zero a column and then another Householder operating from the right to zero most of a row. Now a two-sided QR