Display text string if eigenvalue is complex?

Hi,

I am using the basic eigensolver function to compute the eigenvalues of matrix A and define them in matrix L as follows:

%Define value of A
A=input('Enter Values for Matrix "A" in form [a b;x y]:') 
%Calculate eigenvalues of A
L=eig(A);

As any matrix which could produce complex eigenvalues is not a valid input for this scenario, I would like to be able to display a text string and return the user to a point at which matrix A can be redefined if a complex result is computed.

Any advice on how to do this would be greatly appreciated, this is my first foray into the world of Matlab.

Answer 1

[Andreas Goser]

You could put the INPUT line in a WHILE loop and check with ISREAL whether A is complex or not.