colcomp - column compression, kernel, nullspace

Calling Sequence

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

Parameters

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

Description

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)

Examples

A=rand(5,2)*rand(2,5);
[X,r]=colcomp(A);
norm(A*X(:,1:$-r),1)
 

See Also

rowcomp  fullrf  fullrfk  kernel  

Author

F.D.;