added aliases of selected functions as member functions to LTI

lkies · lkies · commit 13f3870cb8a4 · 2025-01-07T19:54:33.000+01:00
diff --git a/control/__init__.py b/control/__init__.py
@@ -118,5 +118,15 @@
 except ImportError:
     __version__ = "dev"
 
+# patch the LTI class with function aliases for convenience functions
+# this needs to be done after the fact since the modules that contain the functions
+# all heavily depend on the LTI class
+LTI.to_ss = ss
+LTI.to_tf = tf
+LTI.feedback = feedback
+LTI.bode_plot = bode_plot
+LTI.nyquist_plot = nyquist_plot
+LTI.nichols_plot = nichols_plot
+
 # Initialize default parameter values
 reset_defaults()
diff --git a/control/lti.py b/control/lti.py
@@ -11,6 +11,8 @@
 from warnings import warn
 from . import config
 from .iosys import InputOutputSystem
+import control
+from typing import Callable
 
 __all__ = ['poles', 'zeros', 'damp', 'evalfr', 'frequency_response',
            'freqresp', 'dcgain', 'bandwidth', 'LTI']
@@ -203,6 +205,26 @@ def ispassive(self):
         from control.passivity import ispassive
         return ispassive(self)
 
+    # convenience aliases
+    # most function are only forward declaraed and patched in the __init__.py to avoid circular imports
+
+    # conversions
+    to_ss: Callable
+    to_tf: Callable
+
+    # system interconnections
+    feedback: Callable
+
+    # freq domain plotting
+    bode_plot: Callable
+    nyquist_plot: Callable
+    nichols_plot: Callable
+
+    # time domain simulation
+    forced_response = control.timeresp.forced_response
+    impulse_response = control.timeresp.impulse_response
+    step_response = control.timeresp.step_response
+
 
 def poles(sys):
     """
diff --git a/control/statesp.py b/control/statesp.py
@@ -70,6 +70,7 @@
     common_timebase, isdtime, issiso
 from .lti import LTI, _process_frequency_response
 from .nlsys import InterconnectedSystem, NonlinearIOSystem
+import control
 
 try:
     from slycot import ab13dd
@@ -1467,6 +1468,9 @@ def output(self, t, x, u=None, params=None):
                 raise ValueError("len(u) must be equal to number of inputs")
             return (self.C @ x).reshape((-1,)) \
                 + (self.D @ u).reshape((-1,))  # return as row vector
+        
+    # convenience aliase, import needs to go over the submodule to avoid circular imports
+    initial_response = control.timeresp.initial_response
 
 
 class LinearICSystem(InterconnectedSystem, StateSpace):
diff --git a/control/tests/kwargs_test.py b/control/tests/kwargs_test.py
@@ -244,6 +244,7 @@ def test_response_plot_kwargs(data_fcn, plot_fcn, mimo):
     'append': test_unrecognized_kwargs,
     'bode': test_response_plot_kwargs,
     'bode_plot': test_response_plot_kwargs,
+    'LTI.bode_plot': test_response_plot_kwargs,
     'create_estimator_iosystem': stochsys_test.test_estimator_errors,
     'create_statefbk_iosystem': statefbk_test.TestStatefbk.test_statefbk_errors,
     'describing_function_plot': test_matplotlib_kwargs,
@@ -253,6 +254,7 @@ def test_response_plot_kwargs(data_fcn, plot_fcn, mimo):
     'dlqr': test_unrecognized_kwargs,
     'drss': test_unrecognized_kwargs,
     'feedback': test_unrecognized_kwargs,
+    'LTI.feedback': test_unrecognized_kwargs,
     'find_eqpt': iosys_test.test_find_operating_point,
     'find_operating_point': iosys_test.test_find_operating_point,
     'flatsys.flatsys': test_unrecognized_kwargs,
@@ -267,11 +269,13 @@ def test_response_plot_kwargs(data_fcn, plot_fcn, mimo):
     'lqr': test_unrecognized_kwargs,
     'negate': test_unrecognized_kwargs,
     'nichols_plot': test_matplotlib_kwargs,
+    'LTI.nichols_plot': test_matplotlib_kwargs,
     'nichols': test_matplotlib_kwargs,
     'nlsys': test_unrecognized_kwargs,
     'nyquist': test_matplotlib_kwargs,
     'nyquist_response': test_response_plot_kwargs,
     'nyquist_plot': test_matplotlib_kwargs,
+    'LTI.nyquist_plot': test_matplotlib_kwargs,
     'phase_plane_plot': test_matplotlib_kwargs,
     'parallel': test_unrecognized_kwargs,
     'pole_zero_plot': test_unrecognized_kwargs,
