nlev

Leverrier’s algorithm

Calling Sequence

[num,den]=nlev(A,z [,rmax])

Arguments

:A real square matrix : :z character string : :rmax optional parameter (see bdiag) :

Description

[num,den]=nlev(A,z [,rmax]) computes (z*eye()-A)^(-1)

by block diagonalization of A followed by Leverrier’s algorithm on each block.

This algorithm is better than the usual leverrier algorithm but still not perfect!

Examples

A=`rand`_(3,3);x=`poly`_(0,'x');
[NUM,den]=nlev(A,'x')
`clean`_(den-`poly`_(A,'x'))
`clean`_(NUM/den-`inv`_(x*`eye`_()-A))

See Also

• coff resolvent (cofactor method)
• coffg inverse of polynomial matrix
• glever inverse of matrix pencil
• ss2tf conversion from state-space to transfer function