% example 3 for section 6.2: orthogonal matrix
%
v1 = [1 -2 1]'
v2 = [0 1 2]'
v3 = [-5 -2 1]'
A = [v1 v2 v3]
D = A' * A
U = A * D^(-1/2)
U' * U
U * U'