MATLAB Solving Polynomial Eigenvalue Problem

[member 428835]

Hi PF!

I'm trying to solve the polynomial eigenvalue problem $M \lambda^2 + \Phi \lambda + K$ such that

K = [5.92 -.9837;-0.3381 109.94];
I*[14.3 24.04;24.04 40.4];
M = [1 0;0 1];
[f lambda cond] = polyeig(M,Phi,K)

I verify the output of the first eigenvalue via

(M*lambda(1)^2 + Phi*lambda(1) + K)*f(:,1)

and the output has zero real component but non-zero imaginary: $[44i,88i]$. Any ideas what's happening? Condition number is 5, which is evidently sufficiently low to output accurate answers?

 

[jasonRF]

I think you are giving polyeig the arguments in the wrong order.

Jason

 

[member 428835]

I think you are giving polyeig the arguments in the wrong order.

Jason

Thanks!