colregul - removing poles and zeros at infinity
computes a prefilter Ws such that Stmp=Sl*Ws is proper and with full rank D matrix.
Poles at infinity of Sl are moved to alfa ;
Zeros at infinity of Sl are moved to beta ;
Sl is a assumed to be a left invertible linear system ( syslin list) in state-space representation with possibly a polynomial D matrix.
invsyslin , inv , rowregul , rowshuff ,
F. D. , R. N. ;