whitespace xferfcn.py

bnavigator · bnavigator · commit 48241438feb6 · 2020-08-03T00:34:10.000+02:00
diff --git a/control/xferfcn.py b/control/xferfcn.py
@@ -87,21 +87,21 @@ class TransferFunction(LTI):
     means that the numerator of the transfer function from the 6th input to the
     3rd output is set to s^2 + 4s + 8.
 
-    A discrete time transfer function is created by specifying a nonzero 
+    A discrete time transfer function is created by specifying a nonzero
     'timebase' dt when the system is constructed:
 
     * dt = 0: continuous time system (default)
     * dt > 0: discrete time system with sampling period 'dt'
     * dt = True: discrete time with unspecified sampling period
-    * dt = None: no timebase specified 
-
-    Systems must have compatible timebases in order to be combined. A discrete 
-    time system with unspecified sampling time (`dt = True`) can be combined 
-    with a system having a specified sampling time; the result will be a 
-    discrete time system with the sample time of the latter system. Similarly, 
-    a system with timebase `None` can be combined with a system having any 
-    timebase; the result will have the timebase of the latter system. 
-    The default value of dt can be changed by changing the value of 
+    * dt = None: no timebase specified
+
+    Systems must have compatible timebases in order to be combined. A discrete
+    time system with unspecified sampling time (`dt = True`) can be combined
+    with a system having a specified sampling time; the result will be a
+    discrete time system with the sample time of the latter system. Similarly,
+    a system with timebase `None` can be combined with a system having any
+    timebase; the result will have the timebase of the latter system.
+    The default value of dt can be changed by changing the value of
     ``control.config.defaults['control.default_dt']``.
 
     The TransferFunction class defines two constants ``s`` and ``z`` that
@@ -112,7 +112,7 @@ class TransferFunction(LTI):
     >>> s = TransferFunction.s
     >>> G  = (s + 1)/(s**2 + 2*s + 1)
     """
-    
+
     def __init__(self, *args, **kwargs):
         """TransferFunction(num, den[, dt])
 
@@ -212,7 +212,7 @@ def __init__(self, *args, **kwargs):
                 dt = kwargs['dt']
             elif self.is_static_gain():
                 dt = None
-            else: 
+            else:
                 dt = config.defaults['control.default_dt']
         elif len(args) == 3:
             # Discrete time transfer function
@@ -225,7 +225,7 @@ def __init__(self, *args, **kwargs):
             except NameError:   # pragma: no coverage
                 if self.is_static_gain():
                     dt = None
-                else: 
+                else:
                     dt = config.defaults['control.default_dt']
         self.dt = dt
 
@@ -439,7 +439,7 @@ def __mul__(self, other):
         outputs = self.outputs
 
         dt = common_timebase(self.dt, other.dt)
-        
+
         # Preallocate the numerator and denominator of the sum.
         num = [[[0] for j in range(inputs)] for i in range(outputs)]
         den = [[[1] for j in range(inputs)] for i in range(outputs)]
@@ -1003,11 +1003,11 @@ def sample(self, Ts, method='zoh', alpha=None, prewarp_frequency=None):
             The generalized bilinear transformation weighting parameter, which
             should only be specified with method="gbt", and is ignored
             otherwise.
-        
+
         prewarp_frequency : float within [0, infinity)
             The frequency [rad/s] at which to match with the input continuous-
-            time system's magnitude and phase (the gain=1 crossover frequency, 
-            for example). Should only be specified with method='bilinear' or 
+            time system's magnitude and phase (the gain=1 crossover frequency,
+            for example). Should only be specified with method='bilinear' or
             'gbt' with alpha=0.5 and ignored otherwise.
 
         Returns
@@ -1037,7 +1037,7 @@ def sample(self, Ts, method='zoh', alpha=None, prewarp_frequency=None):
         if (method=='bilinear' or (method=='gbt' and alpha==0.5)) and \
                 prewarp_frequency is not None:
             Twarp = 2*np.tan(prewarp_frequency*Ts/2)/prewarp_frequency
-        else: 
+        else:
             Twarp = Ts
         numd, dend, _ = cont2discrete(sys, Twarp, method, alpha)
         return TransferFunction(numd[0, :], dend, Ts)
@@ -1079,13 +1079,13 @@ def _dcgain_cont(self):
         return np.squeeze(gain)
 
     def is_static_gain(self):
-        """returns True if and only if all of the numerator and denominator 
-        polynomials of the (possibly MIMO) transfer funnction are zeroth order, 
+        """returns True if and only if all of the numerator and denominator
+        polynomials of the (possibly MIMO) transfer funnction are zeroth order,
         that is, if the system has no dynamics. """
-        for list_of_polys in self.num, self.den: 
+        for list_of_polys in self.num, self.den:
             for row in list_of_polys:
                 for poly in row:
-                    if len(poly) > 1: 
+                    if len(poly) > 1:
                         return False
         return True
 
