I'm having an issue with the Eigensystem
command. I need to diagonalize a bunch of 3 by 3 complex valued matrices, but more importantly, I need to keep the exact ordering of their eigenvalues once brought to their diagonal form.
For example, if
A = { {1.999, 0.000428712*I, 0} , {-0.000428712*I, 2.00072, 0} , {0, 0, -4.00057} }
then Eigensystem[A]
returns the three eigenvalues (with their corresponding eigenvectors) listed in order of decreasing magnitude (absolute value).
What is even more annoying is if my loop runs into an already diagonal 3 by 3 matrix such as B = {{2,0,0},{0,-3,0},{0,0,2}}
, it will reorder the eigenvalues as {-3,2,2}
.
Is there a command that gives me the eigenvalue without re-sorting them?
Eigensystem
tells you how it reordersB
by giving you the eigenvectors, too. $\endgroup$