colcomp

colcomp — column compression, kernel, nullspace

Calling sequence

[W,rk]=colcomp(A [,flag] [,tol])

`A`	: real or complex matrix
`flag`	: character string
`tol`	: real number
`W`	: square non-singular matrix (change of basis)
`rk`	: integer (rank of `A`)

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)

F.D.;