def pole(self):

"""Compute the poles of a transfer function."""

_, den, denorder = self._common_den(allownonproper=True)

_, den, denorder = self._common_den(allow_nonproper=True)

rts = []

for d, o in zip(den, denorder):

rts.extend(roots(d[:o + 1]))

return out

def _common_den(self, imag_tol=None, allownonproper=False):

def _common_den(self, imag_tol=None, allow_nonproper=False):

"""

Compute MIMO common denominators; return them and adjusted numerators.

Threshold for the imaginary part of a root to use in detecting

complex poles

allownonproper : boolean

allow_nonproper : boolean

Do not enforce proper transfer functions

Returns

gives the numerator coefficient array for the ith output and jth

input; padded for use in td04ad ('C' option); matches the

denorder order; highest coefficient starts on the left.

If allownonproper=True and the order of a numerator exceeds the

order of the common denominator, num will be retured as None

If allow_nonproper=True and the order of a numerator exceeds the

order of the common denominator, num will be returned as None

den: array

sys.inputs by kd

# numerater has a higher order than the denominator, the

# padding will fail

if len(numpoly) > maxindex + 1:

if allownonproper:

if allow_nonproper:

havenonproper = True

break

raise ValueError(