allow FrequencyResponseData signal naming + pandas conversion

murrayrm · murrayrm · commit 51f6bfc21ffb · 2022-04-01T21:19:49.000-07:00
diff --git a/control/frdata.py b/control/frdata.py
@@ -50,12 +50,14 @@
     real, imag, absolute, eye, linalg, where, sort
 from scipy.interpolate import splprep, splev
 from .lti import LTI, _process_frequency_response
+from .exception import pandas_check
+from .namedio import _NamedIOSystem
 from . import config
 
 __all__ = ['FrequencyResponseData', 'FRD', 'frd']
 
 
-class FrequencyResponseData(LTI):
+class FrequencyResponseData(LTI, _NamedIOSystem):
     """FrequencyResponseData(d, w[, smooth])
 
     A class for models defined by frequency response data (FRD).
@@ -152,10 +154,6 @@ def __init__(self, *args, **kwargs):
         # TODO: discrete-time FRD systems?
         smooth = kwargs.pop('smooth', False)
 
-        # Make sure there were no extraneous keywords
-        if kwargs:
-            raise TypeError("unrecognized keywords: ", str(kwargs))
-
         if len(args) == 2:
             if not isinstance(args[0], FRD) and isinstance(args[0], LTI):
                 # not an FRD, but still a system, second argument should be
@@ -196,6 +194,23 @@ def __init__(self, *args, **kwargs):
             raise ValueError(
                 "Needs 1 or 2 arguments; received %i." % len(args))
 
+        # Set the size of the system
+        self.noutputs = self.fresp.shape[0]
+        self.ninputs = self.fresp.shape[1]
+
+        # Process signal names
+        _NamedIOSystem.__init__(
+            self, name=kwargs.pop('name', None),
+            inputs=kwargs.pop('inputs', self.ninputs),
+            outputs=kwargs.pop('outputs', self.noutputs))
+
+        # Keep track of return type
+        self.return_magphase=kwargs.pop('return_magphase', False)
+
+        # Make sure there were no extraneous keywords
+        if kwargs:
+            raise TypeError("unrecognized keywords: ", str(kwargs))
+
         # create interpolation functions
         if smooth:
             self.ifunc = empty((self.fresp.shape[0], self.fresp.shape[1]),
@@ -260,11 +275,13 @@ def __add__(self, other):
 
         # Check that the input-output sizes are consistent.
         if self.ninputs != other.ninputs:
-            raise ValueError("The first summand has %i input(s), but the \
-second has %i." % (self.ninputs, other.ninputs))
+            raise ValueError(
+                "The first summand has %i input(s), but the " \
+                "second has %i." % (self.ninputs, other.ninputs))
         if self.noutputs != other.noutputs:
-            raise ValueError("The first summand has %i output(s), but the \
-second has %i." % (self.noutputs, other.noutputs))
+            raise ValueError(
+                "The first summand has %i output(s), but the " \
+                "second has %i." % (self.noutputs, other.noutputs))
 
         return FRD(self.fresp + other.fresp, other.omega)
 
@@ -551,6 +568,22 @@ def feedback(self, other=1, sign=-1):
 
         return FRD(fresp, other.omega, smooth=(self.ifunc is not None))
 
+    # Convert to pandas
+    def to_pandas(self):
+        if not pandas_check():
+            ImportError('pandas not installed')
+        import pandas
+
+        # Create a dict for setting up the data frame
+        data = {'omega': self.omega}
+        data.update(
+            {'H_{%s, %s}' % (out, inp): self.fresp[i, j] \
+             for i, out in enumerate(self.output_labels) \
+             for j, inp in enumerate(self.input_labels)})
+
+        return pandas.DataFrame(data)
+
+
 #
 # Allow FRD as an alias for the FrequencyResponseData class
 #
diff --git a/control/freqplot.py b/control/freqplot.py
@@ -204,8 +204,9 @@ def bode_plot(syslist, omega=None,
     initial_phase = config._get_param(
         'freqplot', 'initial_phase', kwargs, None, pop=True)
     omega_num = config._get_param('freqplot', 'number_of_samples', omega_num)
+
     # If argument was a singleton, turn it into a tuple
-    if not hasattr(syslist, '__iter__'):
+    if not isinstance(syslist, (list, tuple)):
         syslist = (syslist,)
 
     omega, omega_range_given = _determine_omega_vector(
@@ -678,8 +679,8 @@ def nyquist_plot(syslist, omega=None, plot=True, omega_limits=None,
     indent_direction = config._get_param(
         'nyquist', 'indent_direction', kwargs, _nyquist_defaults, pop=True)
 
-    # If argument was a singleton, turn it into a list
-    if not hasattr(syslist, '__iter__'):
+    # If argument was a singleton, turn it into a tuple
+    if not isinstance(syslist, (list, tuple)):
         syslist = (syslist,)
 
     omega, omega_range_given = _determine_omega_vector(
@@ -1109,7 +1110,7 @@ def singular_values_plot(syslist, omega=None,
     omega_num = config._get_param('freqplot', 'number_of_samples', omega_num)
 
     # If argument was a singleton, turn it into a tuple
-    if not hasattr(syslist, '__iter__'):
+    if not isinstance(syslist, (list, tuple)):
         syslist = (syslist,)
 
     omega, omega_range_given = _determine_omega_vector(
diff --git a/control/tests/frd_test.py b/control/tests/frd_test.py
@@ -15,6 +15,7 @@
 from control.frdata import FRD, _convert_to_FRD, FrequencyResponseData
 from control import bdalg, evalfr, freqplot
 from control.tests.conftest import slycotonly
+from control.exception import pandas_check
 
 
 class TestFRD:
@@ -478,3 +479,43 @@ def test_unrecognized_keyword(self):
         omega = np.logspace(-1, 2, 10)
         with pytest.raises(TypeError, match="unrecognized keyword"):
             frd = FRD(h, omega, unknown=None)
+
+
+def test_named_signals():
+    ct.namedio._NamedIOSystem._idCounter = 0
+    h1 = TransferFunction([1], [1, 2, 2])
+    h2 = TransferFunction([1], [0.1, 1])
+    omega = np.logspace(-1, 2, 10)
+    f1 = FRD(h1, omega)
+    f2 = FRD(h2, omega)
+
+    # Make sure that systems were properly named
+    assert f1.name == 'sys[0]'
+    assert f2.name == 'sys[1]'
+    assert f1.ninputs == 1
+    assert f1.input_labels == ['u[0]']
+    assert f1.noutputs == 1
+    assert f1.output_labels == ['y[0]']
+
+    # Change names
+    f1 = FRD(h1, omega, name='mysys', inputs='u0', outputs='y0')
+    assert f1.name == 'mysys'
+    assert f1.ninputs == 1
+    assert f1.input_labels == ['u0']
+    assert f1.noutputs == 1
+    assert f1.output_labels == ['y0']
+
+
+@pytest.mark.skipif(not pandas_check(), reason="pandas not installed")
+def test_to_pandas():
+    # Create a SISO frequency response
+    h1 = TransferFunction([1], [1, 2, 2])
+    omega = np.logspace(-1, 2, 10)
+    resp = FRD(h1, omega)
+
+    # Convert to pandas
+    df = resp.to_pandas()
+
+    # Check to make sure the data make senses
+    np.testing.assert_equal(df['omega'], resp.omega)
+    np.testing.assert_equal(df['H_{y[0], u[0]}'], resp.fresp[0, 0])
diff --git a/control/tests/type_conversion_test.py b/control/tests/type_conversion_test.py
@@ -185,3 +185,9 @@ def test_binary_op_type_conversions(opname, ltype, rtype, sys_dict):
 
         # Print out what we are testing in case something goes wrong
         assert isinstance(result, type_dict[expected])
+
+        # Make sure that input, output, and state names make sense
+        assert len(result.input_labels) == result.ninputs
+        assert len(result.output_labels) == result.outputs
+        if result.nstates is not None:
+            assert len(result.state_labels) == result.states
