esort sorts the complex continuous eigenvalues in descending
order
esort(p)A vector containing the poles of a transfer-function, zero-pole model or the eigenvalues of a state-matrix
Returns the sorted eigenvalues and the cooresponding indices in a list:
s = sorted eigenvalues idx = index
esort sorts the complex eigenvalues based on their real part. The unstable eigenvalues (positive
real part) are first shown.
This function is used to sort eigenvalues and system poles in damp