function [x] = mnudqrh(A,b)
%MNUDQRH Minimum-norm solution for the underdetermined problem using QR
%x = mnudqrh(A,b) computes the minimum norm solution x to the full rank
%underdetermined system Ax = b using the Householder QR factorization of A
%This program implements Algortihm 7.9.2 of the book.
%input : Matrix A and vector b
%output : vector x
[Q,R] = qr(A');
ran = rank(R);
Q1 = Q(:,1:ran);
R1 = R(1:ran,:);
yr = R1'\b;
x = Q1*yr;