According to the documentation if A is an mxn matrix the function R=qr(A) should return a mxn upper triangular matrix. If I use the following example:
A=[1 0 0 0 ; 0 1 0 1; 0 1 1 0];
R=qr(A)
I get the following output, which is not an upper triangular matrix
R=
1.0000 0 0 0
0 -1.4142 -0.7071 -0.7071
0 0.4142 0.7071 -0.7071
Likewise if I try to compute the "economy size" QR-decomposition via R=qr(A, 0) I also get a matrix that is not upper triangular:
ans =
1.0000 0 0 0
0 -1.4142 -0.7071 -0.7071
0 0.4142 0.7071 -0.7071
If on the other hand I use the code:
A=[1 0 0 0 ; 0 1 0 1; 0 1 1 0];
[Q,R,P]=qr(A);
R = 1.0000 0 0 0
0 -1.4142 -0.7071 -0.7071
0 0 0.7071 -0.7071
I get that R is an upper triangular matrix. Am I misunderstanding the documentation for qr? Ideally I would like to use qr(A,0) to compute the economy QR decomposition of a matrix, but have the output be upper triangular.
