=SET NOECHO 
PROC HH
SET NOWARN
* INPUT a_ 
* OUTPUT P_
* compute the P matrix for the first column
* get the norm of a
* first find the size of a
matrix v_=a_
gen1 NN_=$ROWS
matrix norm_=sqrt(a_'a_)
*print norm_
* Do a Householder Transformation
matrix e_=iden(NN_)
matrix e1_=e_(0,1)
matrix v_=a_+norm_*e1_
*print v_
matrix P_=e_-2*v_*v_'/(v_'v_)
*print P_
=SET WARN 
PROCEND
=SET ECHO