Re: QR decomposition for a special matrix

Sean <guo.xiaoyong@xxxxxxxxx> writes:

Let A be a matrix of the following form

+ + + + +
+ + + + 0
+ 0 + + 0
+ 0 0 + 0
+ 0 0 0 0

i.e., if switch the first column and the last column of A,
the result is a upper triangle matrix


is there any simple algorithm to do the QR decomposition for
such kind of matrix.

If you really need the QR decomposition, I don't think there's
anything simpler than the usual Gram-Schmidt algorithm.
On the other hand, the RQ decomposition would be easy.
--
Robert Israel israel@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Department of Mathematics http://www.math.ubc.ca/~israel
University of British Columbia Vancouver, BC, Canada
.