des2ss

des2ss — descriptor to state-space

Calling sequence

[Sl]=des2ss(A,B,C,D,E [,tol])  
[Sl]=des2ss(Des)

`A,B,C,D,E`	: real matrices of appropriate dimensions
`Des`	: list
`Sl`	: `syslin` list
`tol`	: real parameter (threshold) (default value `100*%eps`).

Descriptor to state-space transform.

Sl=des2ss(A,B,C,D,E) returns a linear system Sl equivalent to the descriptor system (E,A,B,C,D).

For index one (E,A) pencil, explicit formula is used and for higher index pencils rowshuff is used.

Sl=des2ss(Des) with Des=list('des',A,B,C,D,E) returns a linear system Sl in state-space form with possibly a polynomial D matrix.

A generalized Leverrier algorithm is used.



s=poly(0,'s');G=[1/(s-1),s;1,2/s^3];
S1=tf2des(G);S2=tf2des(G,"withD");
W1=des2ss(S1);W2=des2ss(S2);
clean(ss2tf(W1))
clean(ss2tf(W2))