add yfinal parameter to step_info

bnavigator · bnavigator · commit 6587f6922bc5 · 2021-03-19T15:37:55.000+01:00
diff --git a/control/tests/timeresp_test.py b/control/tests/timeresp_test.py
@@ -451,6 +451,15 @@ def assert_step_info_match(self, sys, info, info_ref):
                 # local min/max peak well after signal has risen
                 np.testing.assert_allclose(info[k], info_ref[k], rtol=1e-3)
 
+    @pytest.mark.parametrize(
+        "yfinal", [True, False], ids=["yfinal", "no yfinal"])
+    @pytest.mark.parametrize(
+        "systype, time_2d",
+        [("ltisys", False),
+         ("time response", False),
+         ("time response", True),
+         ],
+        ids=["ltisys", "time response (n,)", "time response (1,n)"])
     @pytest.mark.parametrize(
         "tsystem",
         ["siso_tf_step_matlab",
@@ -459,16 +468,10 @@ def assert_step_info_match(self, sys, info, info_ref):
          "siso_tf_kneg",
          "siso_tf_type1"],
         indirect=["tsystem"])
-    @pytest.mark.parametrize(
-        "systype, time_2d",
-        [("lti", False),
-         ("time response data", False),
-         ("time response data", True),
-         ])
-    def test_step_info(self, tsystem, systype, time_2d):
+    def test_step_info(self, tsystem, systype, time_2d, yfinal):
         """Test step info for SISO systems."""
         step_info_kwargs = tsystem.kwargs.get('step_info', {})
-        if systype == "time response data":
+        if systype == "time response":
             # simulate long enough for steady state value
             tfinal = 3 * tsystem.step_info['SettlingTime']
             if np.isnan(tfinal):
@@ -478,29 +481,37 @@ def test_step_info(self, tsystem, systype, time_2d):
             step_info_kwargs['T'] = t[np.newaxis, :] if time_2d else t
         else:
             sysdata = tsystem.sys
+        if yfinal:
+            step_info_kwargs['yfinal'] = tsystem.step_info['SteadyStateValue']
 
         info = step_info(sysdata, **step_info_kwargs)
 
         self.assert_step_info_match(tsystem.sys, info, tsystem.step_info)
 
+    @pytest.mark.parametrize(
+        "yfinal", [True, False], ids=["yfinal", "no_yfinal"])
+    @pytest.mark.parametrize(
+        "systype", ["ltisys", "time response"])
     @pytest.mark.parametrize(
         "tsystem",
         ['mimo_ss_step_matlab',
          pytest.param('mimo_tf_step', marks=slycotonly)],
         indirect=["tsystem"])
-    @pytest.mark.parametrize(
-        "systype", ["lti", "time response data"])
-    def test_step_info_mimo(self, tsystem, systype):
+    def test_step_info_mimo(self, tsystem, systype, yfinal):
         """Test step info for MIMO systems."""
         step_info_kwargs = tsystem.kwargs.get('step_info', {})
-        if systype == "time response data":
+        if systype == "time response":
             tfinal = 3 * max([S['SettlingTime']
                               for Srow in tsystem.step_info for S in Srow])
             t, y = step_response(tsystem.sys, T=tfinal, T_num=5000)
             sysdata = y
             step_info_kwargs['T'] = t
         else:
             sysdata = tsystem.sys
+        if yfinal:
+            step_info_kwargs['yfinal'] = [[S['SteadyStateValue']
+                                           for S in Srow]
+                                          for Srow in tsystem.step_info]
 
         info_dict = step_info(sysdata, **step_info_kwargs)
 
diff --git a/control/timeresp.py b/control/timeresp.py
@@ -734,8 +734,8 @@ def step_response(sys, T=None, X0=0., input=None, output=None, T_num=None,
         squeeze=squeeze, input=input, output=output)
 
 
-def step_info(sysdata, T=None, T_num=None, SettlingTimeThreshold=0.02,
-              RiseTimeLimits=(0.1, 0.9)):
+def step_info(sysdata, T=None, T_num=None, yfinal=None,
+              SettlingTimeThreshold=0.02, RiseTimeLimits=(0.1, 0.9)):
     """
     Step response characteristics (Rise time, Settling Time, Peak and others).
 
@@ -752,6 +752,11 @@ def step_info(sysdata, T=None, T_num=None, SettlingTimeThreshold=0.02,
         Number of time steps to use in simulation if T is not provided as an
         array; autocomputed if not given; ignored if sysdata is a
         discrete-time system or a time series or response data.
+    yfinal: scalar or array_like, optional
+        Steady-state response. If not given, sysdata.dcgain() is used for
+        systems to simulate and the last value of the the response data is
+        used for a given time series of response data. Scalar for SISO,
+        (noutputs, ninputs) array_like for MIMO systems.
     SettlingTimeThreshold : float value, optional
         Defines the error to compute settling time (default = 0.02)
     RiseTimeLimits : tuple (lower_threshold, upper_theshold)
@@ -838,7 +843,10 @@ def step_info(sysdata, T=None, T_num=None, SettlingTimeThreshold=0.02,
         if T is None or np.asarray(T).size == 1:
             T = _default_time_vector(sysdata, N=T_num, tfinal=T, is_step=True)
         T, Yout = step_response(sysdata, T, squeeze=False)
-        InfValues = np.atleast_2d(sysdata.dcgain())
+        if yfinal:
+            InfValues = np.atleast_2d(yfinal)
+        else:
+            InfValues = np.atleast_2d(sysdata.dcgain())
         retsiso = sysdata.issiso()
         noutputs = sysdata.noutputs
         ninputs = sysdata.ninputs
@@ -864,7 +872,7 @@ def step_info(sysdata, T=None, T_num=None, SettlingTimeThreshold=0.02,
         T = np.squeeze(T)
         noutputs = Yout.shape[0]
         ninputs = Yout.shape[1]
-        InfValues = Yout[:, :, -1]
+        InfValues = np.atleast_2d(yfinal) if yfinal else Yout[:, :, -1]
 
     ret = []
     for i in range(noutputs):
