orth - orthogonal basis
Q=orth(A) returns Q , an orthogonal basis for the span of A . Range( Q ) = Range( A ) and Q'*Q=eye .
The number of columns of Q is the rank of A as determined by the QR algorithm.
A=rand(5,3)*rand(3,4); [X,dim]=rowcomp(A);X=X'; svd([orth(A),X(:,1:dim)])