# nlev

Leverrier's algorithm

### Syntax

`[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 — Co-factors of a matrix of polynomials or rationals
• glever — inverse of matrix pencil
• ss2tf — conversion from state-space to transfer function
 Report an issue << coff State-Space Matrices Subspaces >>

 Copyright (c) 2022-2023 (Dassault Systèmes)Copyright (c) 2017-2022 (ESI Group)Copyright (c) 2011-2017 (Scilab Enterprises)Copyright (c) 1989-2012 (INRIA)Copyright (c) 1989-2007 (ENPC)with contributors Last updated:Mon Mar 27 11:52:43 GMT 2023