hankelsv

hankelsv — Hankel singular values

Calling sequence

[nk2,W]=hankelsv(sl [,tol])  
[nk2]=hankelsv(sl [,tol])

`sl`	: `syslin` list representing the linear system (state-space).
`tol`	: tolerance parameter for detecting imaginary axis modes (default value is `1000*%eps`).

returns nk2, the squared Hankel singular values of sl and W = P*Q = controllability gramian times observability gramian.

nk2 is the vector of eigenvalues of W.



A=diag([-1,-2,-3]);
sl=syslin('c',A,rand(3,2),rand(2,3));[nk2,W]=hankelsv(sl)
[Q,M]=pbig(W,nk2(2)-%eps,'c');
slr=projsl(sl,Q,M);hankelsv(slr)