spoles (Mu Analysis and Synthesis Toolbox)

Calculate the eigenvalues of a SYSTEM A matrix

Syntax

out = spoles(sys)

Description

spoles returns the eigenvalues of the A matrix from the SYSTEM matrix sys.

Examples

Find the poles of the two input, one output, three state SYSTEM matrx sys.

A = [1 1 1; 3 1 1; 1 1 -2]; 
B = 2*ones(3,2); 
C = 3*ones(1,3); 
D = 4*ones(1,2); 
sys = pck(A,B,C,D); 
minfo(sys)
system: 3 states1 outputs2 inputs
spoles(sys)
    3.1474
    -0.8186
    -2.3289
eig(A)
ans =
    3.1474
    -0.8186
    -2.3289

Algorithm

spoles uses the MATLAB command schur to find the eigenvalues of the SYSTEM A matrix. This is a more numerically reliable method than using the eig function.