householder - Householder orthogonal reflexion matrix
given 2 column vectors v, w of same size, householder(v,w) returns a unitary column vector u, such that (eye()-2*u*u')*v is proportional to w. (eye()-2*u*u') is the orthogonal Householder reflexion matrix .
w default value is eye(v). In this case vector (eye()-2*u*u')*v is the vector eye(v)*norm(v).