Reply To: Arbitrary sign for eigen mode

[Guilin Sun]

Yes, I modified, since the minor shifts may cause some issues.

To check the consistency and isolate the issues, a straight waveguide is preferred. The phase is very sensitive to small values, since it is calculated from angle(imag(S)/real(S)). if the imag or the real part is small, due to numberical errors, it can flip the sign of the value. Thus the phase can be quite different. This is not uncommon for phase calculation.