
A = load('t4x4.txt')

x = A(2:end,1);

[v bet] = house(x)

v = [0;v];

H = eye(4) - bet*v*v'

pause

A1 = H*A
pause

A2 = A1*H'
pause

x = A2(3:end,2);

[v bet] = house(x)

v = [0;0; v];

H = eye(4) - bet*v*v'
pause


A3 = H*A2

A4 = A3*H
