Getting flipped eigen values

[Amitkaush]

when i tried for the simpler case of plane Poiseuille flow stability with Alpha=0,beta=1;
instead of getting this eigen spectrum:

i am getting this:

That is real and imaginary parts are flipped.
what can be the possible reason for this.

[frederichecht (Frédéric Hecht)]

With no script and theory no way.