Bug and documentation fixes

ldriever · ldriever · commit a0d26bf4558b · 2020-07-30T20:28:47.000+02:00
The clean_tf function was not making use of the input, output, and precision values passed to it. Fixed this issue. Also extended the documentation to include that the fival function returns None if an unstable system is checked for stability
diff --git a/control/statesp.py b/control/statesp.py
@@ -977,8 +977,9 @@ def fival(self, forcing="step", input=1, output=1, stabilityCheck=False, precisi
 
         Returns
         -------
-        out : float or inf
-            The final value of the system. inf has the correct sign
+        out : float, inf or None
+            The final value of the system. inf has the correct sign. None is returned
+            if stabilityCheck=True and the system is unstable
 
         Raises
         ------
diff --git a/control/timeresp.py b/control/timeresp.py
@@ -910,8 +910,9 @@ def fival(sys, forcing="step", input=1, output=1, stabilityCheck=False, precisio
 
     Returns
     -------
-    out : float or inf
-        The final value of the system. inf has the correct sign
+    out : float, inf or None
+        The final value of the system. inf has the correct sign. None is returned
+        if stabilityCheck=True and the system is unstable
 
     Raises
     ------
diff --git a/control/xferfcn.py b/control/xferfcn.py
@@ -1160,8 +1160,9 @@ def fival(self, forcing="step", input=1, output=1, stabilityCheck=False, precisi
 
         Returns
         -------
-        out : float or inf
-            The final value of the system. inf has the correct sign
+        out : float, inf or None
+            The final value of the system. inf has the correct sign. None is returned
+            if stabilityCheck=True and the system is unstable
 
         Raises
         ------
@@ -1680,7 +1681,7 @@ def clean_tf(sys, input=None, output=None, precision=10):
         raise TypeError("Neither a StateSpace nor TransferFunction was passed to 'sys'")
     if (type(sys) is not TransferFunction):
         sys = tf(sys).minreal()
-    return sys.clean()
+    return sys.clean(input = input, output = output, precision = precision)
 
 
 # Define constants to represent differentiation, unit delay
