colcomp - column compression, kernel, nullspace
Column compression of A : Ac = A*W is column compressed i.e
Ac=[0,Af] with Af full column rank, rank( Af ) = rank( A ) = rk .
flag and tol are optional parameters: flag = 'qr' or 'svd' (default is 'svd' ).
tol = tolerance parameter (of order %eps as default value).
The ma-rk first columns of W span the kernel of A when size(A)=(na,ma)
A=rand(5,2)*rand(2,5); [X,r]=colcomp(A); norm(A*X(:,1:$-r),1)
rowcomp , fullrf , fullrfk , kernel ,
F.D.;