simplify _copy_names, fix docstring errors, add names to sample_syste…

…m and unit tests, namedio.copy is now deepcopy
murrayrm · Nov 26, 2022 · Nov 23, 2022 · Nov 23, 2022 · Nov 23, 2022 · Nov 23, 2022
commit dbf64f2e57bc457a63384424abd32defae2bbd1a
diff --git a/control/dtime.py b/control/dtime.py
@@ -53,7 +53,8 @@
 __all__ = ['sample_system', 'c2d']
 
 # Sample a continuous time system
-def sample_system(sysc, Ts, method='zoh', alpha=None, prewarp_frequency=None):
+def sample_system(sysc, Ts, method='zoh', alpha=None, prewarp_frequency=None,
+        name=None, copy_names=True, **kwargs):
     """
     Convert a continuous time system to discrete time by sampling
 
@@ -72,12 +73,35 @@ def sample_system(sysc, Ts, method='zoh', alpha=None, prewarp_frequency=None):
     prewarp_frequency : float within [0, infinity)
         The frequency [rad/s] at which to match with the input continuous-
         time system's magnitude and phase (only valid for method='bilinear')
+    name : string, optional
+        Set the name of the sampled system.  If not specified and
+        if `copy_names` is `False`, a generic name <sys[id]> is generated
+        with a unique integer id.  If `copy_names` is `True`, the new system
+        name is determined by adding the prefix and suffix strings in
+        config.defaults['namedio.sampled_system_name_prefix'] and
+        config.defaults['namedio.sampled_system_name_suffix'], with the
+        default being to add the suffix '$sampled'.
+    copy_names : bool, Optional
+        If True, copy the names of the input signals, output
+        signals, and states to the sampled system.
 
     Returns
     -------
     sysd : linsys
         Discrete time system, with sampling rate Ts
 
+    Additional Parameters
+    ---------------------
+    inputs : int, list of str or None, optional
+        Description of the system inputs.  If not specified, the origional
+        system inputs are used.  See :class:`NamedIOSystem` for more
+        information.
+    outputs : int, list of str or None, optional
+        Description of the system outputs.  Same format as `inputs`.
+    states : int, list of str, or None, optional
+        Description of the system states.  Same format as `inputs`. Only
+        available if the system is :class:`StateSpace`.
+
     Notes
     -----
     See :meth:`StateSpace.sample` or :meth:`TransferFunction.sample` for
@@ -94,7 +118,8 @@ def sample_system(sysc, Ts, method='zoh', alpha=None, prewarp_frequency=None):
         raise ValueError("First argument must be continuous time system")
 
     return sysc.sample(Ts,
-        method=method, alpha=alpha, prewarp_frequency=prewarp_frequency)
+        method=method, alpha=alpha, prewarp_frequency=prewarp_frequency,
+        name=name, copy_names=copy_names, **kwargs)
 
 
 def c2d(sysc, Ts, method='zoh', prewarp_frequency=None):

diff --git a/control/iosys.py b/control/iosys.py
@@ -568,16 +568,23 @@ def linearize(self, x0, u0, t=0, params=None, eps=1e-6,
             StateSpace(A, B, C, D, self.dt, remove_useless_states=False))
 
         # Set the system name, inputs, outputs, and states
+        if copy in kwargs:
+            copy_names = kwargs.pop('copy')
+            warn("keyword 'copy' is deprecated. please use 'copy_names'",
+                DeprecationWarning)
+
         if copy_names:
+            linsys._copy_names(self)
             if name is None:
-                name = \
-                    config.defaults['namedio.linearized_system_name_prefix'] +\
-                    self.name + \
+                linsys.name = \
+                    config.defaults['namedio.linearized_system_name_prefix']+\
+                    linsys.name+\
                     config.defaults['namedio.linearized_system_name_suffix']
-            linsys._copy_names(self, name=name)
-        linsys = LinearIOSystem(linsys, name=name, **kwargs)
-        return linsys
+            else:
+                linsys.name = name
 
+        # re-init to include desired signal names if names were provided
+        return LinearIOSystem(linsys, **kwargs)
 
 class LinearIOSystem(InputOutputSystem, StateSpace):
     """Input/output representation of a linear (state space) system.
@@ -2180,19 +2187,17 @@ def linearize(sys, xeq, ueq=None, t=0, params=None, **kw):
     params : dict, optional
         Parameter values for the systems.  Passed to the evaluation functions
         for the system as default values, overriding internal defaults.
-    copy_names : bool, Optional
-        If `copy_names` is True, copy the names of the input signals, output 
-        signals, and states to the linearized system.  If `name` is not 
-        specified, the system name is set to the input system name with the 
-        string '_linearized' appended.
     name : string, optional
         Set the name of the linearized system.  If not specified and
-        if `copy` is `False`, a generic name <sys[id]> is generated
-        with a unique integer id.  If `copy` is `True`, the new system
+        if `copy_names` is `False`, a generic name <sys[id]> is generated
+        with a unique integer id.  If `copy_names` is `True`, the new system
         name is determined by adding the prefix and suffix strings in
         config.defaults['namedio.linearized_system_name_prefix'] and
         config.defaults['namedio.linearized_system_name_suffix'], with the
         default being to add the suffix '$linearized'.
+    copy_names : bool, Optional
+        If True, Copy the names of the input signals, output signals, and
+        states to the linearized system.
 
     Returns
     -------

diff --git a/control/namedio.py b/control/namedio.py
@@ -6,7 +6,7 @@
 # and other similar classes to allow naming of signals.
 
 import numpy as np
-from copy import copy
+from copy import deepcopy
 from warnings import warn
 from . import config
 
@@ -99,13 +99,10 @@ def __str__(self):
     def _find_signal(self, name, sigdict):
         return sigdict.get(name, None)
 
-    def _copy_names(self, sys, name=None):
+    def _copy_names(self, sys):
         """copy the signal and system name of sys. Name is given as a keyword
         in case a specific name (e.g. append 'linearized') is desired. """
-        if name is None: 
-            self.name = sys.name
-        else:
-            self.name = name
+        self.name = sys.name
         self.ninputs, self.input_index = \
             sys.ninputs, sys.input_index.copy()
         self.noutputs, self.output_index = \
@@ -126,7 +123,7 @@ def copy(self, name=None, use_prefix_suffix=True):
 
         """
         # Create a copy of the system
-        newsys = copy(self)
+        newsys = deepcopy(self)
 
         # Update the system name
         if name is None and use_prefix_suffix:

diff --git a/control/statesp.py b/control/statesp.py
@@ -357,7 +357,7 @@ def __init__(self, *args, init_namedio=True, **kwargs):
                 states=states, dt=dt)
         elif kwargs:
             raise TypeError("unrecognized keyword(s): ", str(kwargs))
-        
+
         # Reset shapes (may not be needed once np.matrix support is removed)
         if self._isstatic():
             # static gain
@@ -1298,7 +1298,7 @@ def __getitem__(self, indices):
         return StateSpace(self.A, self.B[:, j], self.C[i, :],
                           self.D[i, j], self.dt)
 
-    def sample(self, Ts, method='zoh', alpha=None, prewarp_frequency=None, 
+    def sample(self, Ts, method='zoh', alpha=None, prewarp_frequency=None,
                name=None, copy_names=True, **kwargs):
         """Convert a continuous time system to discrete time
 
@@ -1327,19 +1327,17 @@ def sample(self, Ts, method='zoh', alpha=None, prewarp_frequency=None,
             time system's magnitude and phase (the gain=1 crossover frequency,
             for example). Should only be specified with method='bilinear' or
             'gbt' with alpha=0.5 and ignored otherwise.
-        copy_names : bool, Optional
-            If `copy_names` is True, copy the names of the input signals, output 
-            signals, and states to the sampled system.  If `name` is not 
-            specified, the system name is set to the input system name with the 
-            string '_sampled' appended.
         name : string, optional
             Set the name of the sampled system.  If not specified and
-            if `copy` is `False`, a generic name <sys[id]> is generated
-            with a unique integer id.  If `copy` is `True`, the new system
+            if `copy_names` is `False`, a generic name <sys[id]> is generated
+            with a unique integer id.  If `copy_names` is `True`, the new system
             name is determined by adding the prefix and suffix strings in
             config.defaults['namedio.sampled_system_name_prefix'] and
             config.defaults['namedio.sampled_system_name_suffix'], with the
             default being to add the suffix '$sampled'.
+        copy_names : bool, Optional
+            If True, copy the names of the input signals, output
+            signals, and states to the sampled system.
 
         Returns
         -------
@@ -1380,15 +1378,16 @@ def sample(self, Ts, method='zoh', alpha=None, prewarp_frequency=None,
         sysd = StateSpace(Ad, Bd, C, D, Ts)
         # copy over the system name, inputs, outputs, and states
         if copy_names:
+            sysd._copy_names(self)
             if name is None:
-                name = \
+                sysd.name = \
                     config.defaults['namedio.sampled_system_name_prefix'] +\
-                    self.name + \
+                    sysd.name + \
                     config.defaults['namedio.sampled_system_name_suffix']
-            sysd._copy_names(self, name=name)
-        # pass desired signal names if names were provided        
-        sysd = StateSpace(sysd, name=name, **kwargs)
-        return sysd
+            else:
+                sysd.name = name
+        # pass desired signal names if names were provided
+        return StateSpace(sysd, **kwargs)
 
     def dcgain(self, warn_infinite=False):
         """Return the zero-frequency gain

diff --git a/control/tests/discrete_test.py b/control/tests/discrete_test.py
@@ -458,4 +458,47 @@ def test_signal_names(self, tsys):
         assert ssd.state_labels == ['a', 'b', 'c']
         assert ssd.output_labels == ['y']
         assert tfd.input_labels == ['u']
-        assert tfd.output_labels == ['y']
+        assert tfd.output_labels == ['y']
+
+        ssd = sample_system(ssc, 0.1)
+        tfd = sample_system(tfc, 0.1)
+        assert ssd.input_labels == ['u']
+        assert ssd.state_labels == ['a', 'b', 'c']
+        assert ssd.output_labels == ['y']
+        assert tfd.input_labels == ['u']
+        assert tfd.output_labels == ['y']
+
+        # system names and signal name override
+        sysc = StateSpace(1.1, 1, 1, 1, inputs='u', outputs='y', states='a')
+
+        sysd = sample_system(sysc, 0.1, name='sampled')
+        assert sysd.name == 'sampled'
+        assert sysd.find_input('u') == 0
+        assert sysd.find_output('y') == 0
+        assert sysd.find_state('a') == 0
+
+        # If we copy signal names w/out a system name, append '$sampled'
+        sysd = sample_system(sysc, 0.1)
+        assert sysd.name == sysc.name + '$sampled'
+
+        # If copy is False, signal names should not be copied
+        sysd_nocopy = sample_system(sysc, 0.1, copy_names=False)
+        assert sysd_nocopy.find_input('u') is None
+        assert sysd_nocopy.find_output('y') is None
+        assert sysd_nocopy.find_state('a') is None
+
+        # if signal names are provided, they should override those of sysc
+        sysd_newnames = sample_system(sysc, 0.1, 
+            inputs='v', outputs='x', states='b')
+        assert sysd_newnames.find_input('v') == 0
+        assert sysd_newnames.find_input('u') is None
+        assert sysd_newnames.find_output('x') == 0
+        assert sysd_newnames.find_output('y') is None
+        assert sysd_newnames.find_state('b') == 0
+        assert sysd_newnames.find_state('a') is None        
+        # test just one name
+        sysd_newnames = sample_system(sysc, 0.1, inputs='v')
+        assert sysd_newnames.find_input('v') == 0
+        assert sysd_newnames.find_input('u') is None
+        assert sysd_newnames.find_output('y') == 0
+        assert sysd_newnames.find_output('x') is None
diff --git a/control/tests/iosys_test.py b/control/tests/iosys_test.py
@@ -231,12 +231,6 @@ def test_linearize_named_signals(self, kincar):
         linearized = kincar.linearize([0, 0, 0], [0, 0], copy_names=True)
         assert linearized.name == kincar.name + '$linearized'
 
-        # Test legacy version as well
-        ct.use_legacy_defaults('0.8.4')
-        ct.config.use_numpy_matrix(False)       # np.matrix deprecated
-        linearized = kincar.linearize([0, 0, 0], [0, 0], copy_names=True)
-        assert linearized.name == kincar.name + '_linearized'
-
         # If copy is False, signal names should not be copied
         lin_nocopy = kincar.linearize(0, 0, copy_names=False)
         assert lin_nocopy.find_input('v') is None
@@ -257,6 +251,12 @@ def test_linearize_named_signals(self, kincar):
         assert linearized_newnames.find_output('x') is None
         assert linearized_newnames.find_output('y') is None
 
+        # Test legacy version as well
+        ct.use_legacy_defaults('0.8.4')
+        ct.config.use_numpy_matrix(False)       # np.matrix deprecated
+        linearized = kincar.linearize([0, 0, 0], [0, 0], copy_names=True)
+        assert linearized.name == kincar.name + '_linearized'
+
     def test_connect(self, tsys):
         # Define a couple of (linear) systems to interconnection
         linsys1 = tsys.siso_linsys

diff --git a/control/tests/kwargs_test.py b/control/tests/kwargs_test.py
@@ -183,6 +183,7 @@ def test_matplotlib_kwargs(function, nsysargs, moreargs, kwargs, mplcleanup):
     'tf': test_unrecognized_kwargs,
     'tf2io' : test_unrecognized_kwargs,
     'tf2ss' : test_unrecognized_kwargs,
+    'sample_system' : test_unrecognized_kwargs,
     'flatsys.point_to_point':
         flatsys_test.TestFlatSys.test_point_to_point_errors,
     'flatsys.solve_flat_ocp':

diff --git a/control/xferfcn.py b/control/xferfcn.py
@@ -1090,7 +1090,7 @@ def _common_den(self, imag_tol=None, allow_nonproper=False):
 
         return num, den, denorder
 
-    def sample(self, Ts, method='zoh', alpha=None, prewarp_frequency=None, 
+    def sample(self, Ts, method='zoh', alpha=None, prewarp_frequency=None,
                name=None, copy_names=True, **kwargs):
         """Convert a continuous-time system to discrete time
 
@@ -1119,19 +1119,17 @@ def sample(self, Ts, method='zoh', alpha=None, prewarp_frequency=None,
             time system's magnitude and phase (the gain=1 crossover frequency,
             for example). Should only be specified with method='bilinear' or
             'gbt' with alpha=0.5 and ignored otherwise.
-        copy_names : bool, Optional
-            If `copy_names` is True, copy the names of the input signals, output 
-            signals, and states to the sampled system.  If `name` is not 
-            specified, the system name is set to the input system name with the 
-            string '_sampled' appended.
         name : string, optional
             Set the name of the sampled system.  If not specified and
-            if `copy` is `False`, a generic name <sys[id]> is generated
-            with a unique integer id.  If `copy` is `True`, the new system
+            if `copy_names` is `False`, a generic name <sys[id]> is generated
+            with a unique integer id.  If `copy_names` is `True`, the new system
             name is determined by adding the prefix and suffix strings in
             config.defaults['namedio.sampled_system_name_prefix'] and
             config.defaults['namedio.sampled_system_name_suffix'], with the
             default being to add the suffix '$sampled'.
+        copy_names : bool, Optional
+            If True, copy the names of the input signals, output
+            signals, and states to the sampled system.
 
         Returns
         -------
@@ -1146,8 +1144,6 @@ def sample(self, Ts, method='zoh', alpha=None, prewarp_frequency=None,
             information.
         outputs : int, list of str or None, optional
             Description of the system outputs.  Same format as `inputs`.
-        states : int, list of str, or None, optional
-            Description of the system states.  Same format as `inputs`.
 
         Notes
         -----
@@ -1178,15 +1174,16 @@ def sample(self, Ts, method='zoh', alpha=None, prewarp_frequency=None,
         sysd = TransferFunction(numd[0, :], dend, Ts)
         # copy over the system name, inputs, outputs, and states
         if copy_names:
+            sysd._copy_names(self)
             if name is None:
-                name = \
+                sysd.name = \
                     config.defaults['namedio.sampled_system_name_prefix'] +\
-                    self.name + \
+                    sysd.name + \
                     config.defaults['namedio.sampled_system_name_suffix']
-            sysd._copy_names(self, name=name)
-        # pass desired signal names if names were provided        
-        sysd = TransferFunction(sysd, name=name, **kwargs)
-        return sysd
+            else:
+                sysd.name = name
+        # pass desired signal names if names were provided
+        return TransferFunction(sysd, name=name, **kwargs)
 
     def dcgain(self, warn_infinite=False):
         """Return the zero-frequency (or DC) gain