initial pass at defining lists of systems for time responses

murrayrm · murrayrm · commit 95326b0f0bea · 2024-06-29T12:41:18.000-07:00
diff --git a/control/nlsys.py b/control/nlsys.py
@@ -1317,7 +1317,7 @@ def nlsys(
 
 
 def input_output_response(
-        sys, T, U=0., X0=0, params=None, ignore_errors=False,
+        sysdata, T, U=0., X0=0, params=None, ignore_errors=False,
         transpose=False, return_x=False, squeeze=None,
         solve_ivp_kwargs=None, t_eval='T', **kwargs):
     """Compute the output response of a system to a given input.
@@ -1327,8 +1327,8 @@ def input_output_response(
 
     Parameters
     ----------
-    sys : InputOutputSystem
-        Input/output system to simulate.
+    sysdata : I/O system or list of I/O systems
+        I/O system(s) for which input/output response is simulated.
 
     T : array-like
         Time steps at which the input is defined; values must be evenly spaced.
@@ -1448,6 +1448,15 @@ def input_output_response(
     if kwargs:
         raise TypeError("unrecognized keyword(s): ", str(kwargs))
 
+    # Convert the first argument to a list
+    syslist = sysdata if isinstance(sysdata, (list, tuple)) else [sysdata]
+
+    # TODO: implement step responses for multiple systems
+    if len(syslist) > 1:
+        raise NotImplementedError(
+            "step responses for multiple systems not yet implemented")
+    sys = syslist[0]
+
     # Sanity checking on the input
     if not isinstance(sys, NonlinearIOSystem):
         raise TypeError("System of type ", type(sys), " not valid")
diff --git a/control/tests/timeplot_test.py b/control/tests/timeplot_test.py
@@ -313,6 +313,14 @@ def test_combine_time_responses():
         combresp6 = ct.combine_time_responses([resp1, resp])
 
 
+def test_list_responses():
+    sys1 = ct.rss(2, 2, 2)
+    sys2 = ct.rss(2, 2, 2)
+
+    resp = ct.step_response([sys1, sys2]).plot()
+    assert resp.ntraces == 2
+
+
 @slycotonly
 def test_linestyles():
     # Check to make sure we can change line styles
diff --git a/control/timeresp.py b/control/timeresp.py
@@ -1280,8 +1280,9 @@ def _process_time_response(
     return tout, yout
 
 
-def step_response(sys, T=None, X0=0, input=None, output=None, T_num=None,
-                  transpose=False, return_x=False, squeeze=None, params=None):
+def step_response(
+        sysdata, T=None, X0=0, input=None, output=None, T_num=None,
+        transpose=False, return_x=False, squeeze=None, params=None):
     # pylint: disable=W0622
     """Compute the step response for a linear system.
 
@@ -1296,8 +1297,8 @@ def step_response(sys, T=None, X0=0, input=None, output=None, T_num=None,
 
     Parameters
     ----------
-    sys : StateSpace or TransferFunction
-        LTI system to simulate
+    sysdata : I/O system or list of I/O systems
+        I/O system(s) for which step response is computed.
 
     T : array_like or float, optional
         Time vector, or simulation time duration if a number. If T is not
@@ -1391,6 +1392,15 @@ def step_response(sys, T=None, X0=0, input=None, output=None, T_num=None,
     from .statesp import _convert_to_statespace
     from .xferfcn import TransferFunction
 
+    # Convert the first argument to a list
+    syslist = sysdata if isinstance(sysdata, (list, tuple)) else [sysdata]
+
+    # TODO: implement step responses for multiple systems
+    if len(syslist) > 1:
+        raise NotImplementedError(
+            "step responses for multiple systems not yet implemented")
+    sys = syslist[0]
+
     # Create the time and input vectors
     if T is None or np.asarray(T).size == 1:
         T = _default_time_vector(sys, N=T_num, tfinal=T, is_step=True)
@@ -1681,8 +1691,9 @@ def step_info(sysdata, T=None, T_num=None, yfinal=None, params=None,
     return ret[0][0] if retsiso else ret
 
 
-def initial_response(sys, T=None, X0=0, output=None, T_num=None, params=None,
-                     transpose=False, return_x=False, squeeze=None):
+def initial_response(
+        sysdata, T=None, X0=0, output=None, T_num=None, params=None,
+        transpose=False, return_x=False, squeeze=None):
     # pylint: disable=W0622
     """Compute the initial condition response for a linear system.
 
@@ -1695,6 +1706,9 @@ def initial_response(sys, T=None, X0=0, output=None, T_num=None, params=None,
 
     Parameters
     ----------
+    sysdata : I/O system or list of I/O systems
+        I/O system(s) for which initial response is computed.
+
     sys : StateSpace or TransferFunction
         LTI system to simulate
 
@@ -1773,6 +1787,15 @@ def initial_response(sys, T=None, X0=0, output=None, T_num=None, params=None,
     """
     from .lti import LTI
 
+    # Convert the first argument to a list
+    syslist = sysdata if isinstance(sysdata, (list, tuple)) else [sysdata]
+
+    # TODO: implement step responses for multiple systems
+    if len(syslist) > 1:
+        raise NotImplementedError(
+            "step responses for multiple systems not yet implemented")
+    sys = syslist[0]
+
     # Create the time and input vectors
     if T is None or np.asarray(T).size == 1:
         T = _default_time_vector(sys, N=T_num, tfinal=T, is_step=False)
@@ -1800,8 +1823,9 @@ def initial_response(sys, T=None, X0=0, output=None, T_num=None, params=None,
         transpose=transpose, return_x=return_x, squeeze=squeeze)
 
 
-def impulse_response(sys, T=None, input=None, output=None, T_num=None,
-                     transpose=False, return_x=False, squeeze=None):
+def impulse_response(
+        sysdata, T=None, input=None, output=None, T_num=None,
+        transpose=False, return_x=False, squeeze=None):
     # pylint: disable=W0622
     """Compute the impulse response for a linear system.
 
@@ -1816,8 +1840,8 @@ def impulse_response(sys, T=None, input=None, output=None, T_num=None,
 
     Parameters
     ----------
-    sys : StateSpace, TransferFunction
-        LTI system to simulate
+    sysdata : I/O system or list of I/O systems
+        I/O system(s) for which impluse response is computed.
 
     T : array_like or float, optional
         Time vector, or simulation time duration if a scalar (time vector is
@@ -1896,6 +1920,15 @@ def impulse_response(sys, T=None, input=None, output=None, T_num=None,
     from .lti import LTI
     from .statesp import _convert_to_statespace
 
+    # Convert the first argument to a list
+    syslist = sysdata if isinstance(sysdata, (list, tuple)) else [sysdata]
+
+    # TODO: implement step responses for multiple systems
+    if len(syslist) > 1:
+        raise NotImplementedError(
+            "step responses for multiple systems not yet implemented")
+    sys = syslist[0]
+
     # Make sure we have an LTI system
     if not isinstance(sys, LTI):
         raise ValueError("system must be LTI system for impulse response")
