move warning to before conversion

bnavigator · bnavigator · commit 97e08c6f0a6a · 2021-03-25T13:23:14.000+01:00
diff --git a/control/timeresp.py b/control/timeresp.py
@@ -302,6 +302,13 @@ def forced_response(sys, T=None, U=0., X0=0., transpose=False,
             "return_x specified for a transfer function system. Internal "
             "conversion to state space used; results may meaningless.")
 
+    # If we are passed a transfer function and X0 is non-zero, warn the user
+    if isinstance(sys, TransferFunction) and np.any(X0 != 0):
+        warnings.warn(
+            "Non-zero initial condition given for transfer function system. "
+            "Internal conversion to state space used; may not be consistent "
+            "with given X0.")
+
     sys = _convert_to_statespace(sys)
     A, B, C, D = np.asarray(sys.A), np.asarray(sys.B), np.asarray(sys.C), \
         np.asarray(sys.D)
@@ -358,12 +365,6 @@ def forced_response(sys, T=None, U=0., X0=0., transpose=False,
     X0 = _check_convert_array(X0, [(n_states,), (n_states, 1)],
                               'Parameter ``X0``: ', squeeze=True)
 
-    # If we are passed a transfer function and X0 is non-zero, warn the user
-    if isinstance(sys, TransferFunction) and np.any(X0 != 0):
-        warnings.warn(
-            "Non-zero initial condition given for transfer function system. "
-            "Internal conversion to state space used; may not be consistent "
-            "with given X0.")
 
     xout = np.zeros((n_states, n_steps))
     xout[:, 0] = X0
diff --git a/doc/conventions.rst b/doc/conventions.rst
@@ -83,17 +83,17 @@ The timebase argument can be given when a 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 
+* dt = None: no timebase specified
 
 Only the :class:`StateSpace`, :class:`TransferFunction`, and
 :class:`InputOutputSystem` classes allow explicit representation of
 discrete time systems.
 
-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 
+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 a specified
-timebase; the result will have the timebase of the latter system. For continuous 
+timebase; the result will have the timebase of the latter system. For continuous
 time systems, the :func:`sample_system` function or the :meth:`StateSpace.sample` and :meth:`TransferFunction.sample` methods
 can be used to create a discrete time system from a continuous time system.
 See :ref:`utility-and-conversions`. The default value of 'dt' can be changed by
@@ -179,6 +179,10 @@ can be computed like this::
 
     ft = D * U
 
+
+.. currentmodule:: control
+.. _package-configuration-parameters:
+
 Package configuration parameters
 ================================
 
@@ -207,25 +211,25 @@ on standard configurations.
 Selected variables that can be configured, along with their default values:
 
   * bode.dB (False): Bode plot magnitude plotted in dB (otherwise powers of 10)
-    
+
   * bode.deg (True): Bode plot phase plotted in degrees (otherwise radians)
-    
+
   * bode.Hz (False): Bode plot frequency plotted in Hertz (otherwise rad/sec)
-    
+
   * bode.grid (True): Include grids for magnitude and phase plots
-    
+
   * freqplot.number_of_samples (None): Number of frequency points in Bode plots
-    
+
   * freqplot.feature_periphery_decade (1.0): How many decades to include in the
     frequency range on both sides of features (poles, zeros).
-    
+
   * statesp.use_numpy_matrix (True): set the return type for state space matrices to
     `numpy.matrix` (verus numpy.ndarray)
 
-  * statesp.default_dt and xferfcn.default_dt (None): set the default value of dt when 
+  * statesp.default_dt and xferfcn.default_dt (None): set the default value of dt when
     constructing new LTI systems
 
-  * statesp.remove_useless_states (True): remove states that have no effect on the 
+  * statesp.remove_useless_states (True): remove states that have no effect on the
     input-output dynamics of the system
 
 Additional parameter variables are documented in individual functions
