Given a QR factorization of a real or complex matrix
A = Q*R, Q unitary and
R upper trapezoidal, return the QR factorization
of A(:,p), where p is the permutation
p = [1:i-1, shift(i:j, 1), j+1:n]
if i < j
or
p = [1:j-1, shift(j:i,-1), i+1:n]
if j < i.
See also: qr, qrupdate, qrinsert, qrdelete.
Package: octave