python-control · murrayrm · Feb 3, 2025 · Jan 25, 2025 · Feb 1, 2025 · Feb 1, 2025
diff --git a/.github/workflows/ruff-check.yml b/.github/workflows/ruff-check.yml
@@ -0,0 +1,29 @@
+# run ruff check on library source
+# TODO: extend to tests, examples, benchmarks
+
+name: ruff-check
+
+on: [push, pull_request]
+
+jobs:
+  ruff-check-linux:
+    # ruff *shouldn't* be sensitive to platform
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout python-control
+      uses: actions/checkout@v3
+
+    - name: Setup environment
+      uses: actions/setup-python@v4
+      with:
+        python-version: 3.13 # todo: latest?
+
+    - name: Install ruff
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install ruff
+
+    - name: Run ruff check
+      run: |
+        ruff check
diff --git a/control/__init__.py b/control/__init__.py
@@ -70,6 +70,11 @@
 # Import functions from within the control system library
 # Note: the functions we use are specified as __all__ variables in the modules
 
+# don't warn about `import *`
+# ruff: noqa: F403
+# don't warn about unknown names; they come via `import *`
+# ruff: noqa: F405
+
 # Input/output system modules
 from .iosys import *
 from .nlsys import *
@@ -106,8 +111,8 @@
 from .sysnorm import *
 
 # Allow access to phase_plane functions as ct.phaseplot.fcn or ct.pp.fcn
-from . import phaseplot
-from . import phaseplot as pp
+from . import phaseplot as phaseplot
+pp = phaseplot
 
 # Exceptions
 from .exception import *

diff --git a/control/canonical.py b/control/canonical.py
@@ -8,9 +8,8 @@
 
 import numpy as np
 
-from numpy import zeros, zeros_like, shape, poly, iscomplex, vstack, hstack, \
-    transpose, empty, finfo, float64
-from numpy.linalg import solve, matrix_rank, eig
+from numpy import zeros_like, poly, transpose
+from numpy.linalg import solve, matrix_rank
 
 from scipy.linalg import schur
 

diff --git a/control/dtime.py b/control/dtime.py
@@ -48,7 +48,6 @@
 """
 
 from .iosys import isctime
-from .statesp import StateSpace
 
 __all__ = ['sample_system', 'c2d']
 

diff --git a/control/exception.py b/control/exception.py
@@ -71,7 +71,7 @@ def slycot_check():
     global slycot_installed
     if slycot_installed is None:
         try:
-            import slycot
+            import slycot # noqa: F401
             slycot_installed = True
         except:
             slycot_installed = False
@@ -85,7 +85,7 @@ def pandas_check():
     global pandas_installed
     if pandas_installed is None:
         try:
-            import pandas
+            import pandas # noqa: F401
             pandas_installed = True
         except:
             pandas_installed = False
@@ -98,7 +98,7 @@ def cvxopt_check():
     global cvxopt_installed
     if cvxopt_installed is None:
         try:
-            import cvxopt
+            import cvxopt # noqa: F401
             cvxopt_installed = True
         except:
             cvxopt_installed = False

diff --git a/control/flatsys/__init__.py b/control/flatsys/__init__.py
@@ -61,15 +61,17 @@
 """
 
 # Basis function families
-from .basis import BasisFamily
-from .poly import PolyFamily
-from .bezier import BezierFamily
-from .bspline import BSplineFamily
+from .basis import BasisFamily as BasisFamily
+from .poly import PolyFamily as PolyFamily
+from .bezier import BezierFamily as BezierFamily
+from .bspline import BSplineFamily as BSplineFamily
 
 # Classes
-from .systraj import SystemTrajectory
-from .flatsys import FlatSystem, flatsys
-from .linflat import LinearFlatSystem
+from .systraj import SystemTrajectory as SystemTrajectory
+from .flatsys import FlatSystem as FlatSystem
+from .flatsys import flatsys as flatsys
+from .linflat import LinearFlatSystem as LinearFlatSystem
 
 # Package functions
-from .flatsys import point_to_point, solve_flat_ocp
+from .flatsys import point_to_point as point_to_point
+from .flatsys import solve_flat_ocp as solve_flat_ocp
diff --git a/control/flatsys/bspline.py b/control/flatsys/bspline.py
@@ -8,7 +8,7 @@
 
 import numpy as np
 from .basis import BasisFamily
-from scipy.interpolate import BSpline, splev
+from scipy.interpolate import BSpline
 
 class BSplineFamily(BasisFamily):
     """B-spline basis functions.

diff --git a/control/flatsys/flatsys.py b/control/flatsys/flatsys.py
@@ -8,6 +8,7 @@
 import warnings
 from .poly import PolyFamily
 from .systraj import SystemTrajectory
+from ..exception import ControlArgument
 from ..nlsys import NonlinearIOSystem
 from ..timeresp import _check_convert_array
 
@@ -245,7 +246,6 @@ def flatsys(*args, updfcn=None, outfcn=None, **kwargs):
     """
     from .linflat import LinearFlatSystem
     from ..statesp import StateSpace
-    from ..iosys import _process_iosys_keywords
 
     if len(args) == 1 and isinstance(args[0], StateSpace):
         # We were passed a linear system, so call linflat

diff --git a/control/frdata.py b/control/frdata.py
@@ -15,8 +15,8 @@
 from warnings import warn
 
 import numpy as np
-from numpy import absolute, angle, array, empty, eye, imag, linalg, ones, \
-    real, sort, where
+from numpy import absolute, array, empty, eye, imag, linalg, ones, \
+    real, sort
 from scipy.interpolate import splev, splprep
 
 from . import config

diff --git a/control/freqplot.py b/control/freqplot.py
@@ -11,7 +11,6 @@
 import itertools
 import math
 import warnings
-from os.path import commonprefix
 
 import matplotlib as mpl
 import matplotlib.pyplot as plt
@@ -760,13 +759,11 @@ def _make_line_label(response, output_index, input_index):
             if plot_magnitude:
                 ax_mag.axhline(y=0 if dB else 1, color='k', linestyle=':',
                                zorder=-20)
-                mag_ylim = ax_mag.get_ylim()
 
             if plot_phase:
                 ax_phase.axhline(y=phase_limit if deg else
                                  math.radians(phase_limit),
                                  color='k', linestyle=':', zorder=-20)
-                phase_ylim = ax_phase.get_ylim()
 
             # Annotate the phase margin (if it exists)
             if plot_phase and pm != float('inf') and Wcp != float('nan'):
@@ -2222,7 +2219,7 @@ def gangof4_plot(
         See :class:`ControlPlot` for more detailed information.
 
     """
-    if len(args) == 1 and isinstance(arg, FrequencyResponseData):
+    if len(args) == 1 and isinstance(args[0], FrequencyResponseData):
         if any([kw is not None
                 for kw in [omega, omega_limits, omega_num, Hz]]):
             raise ValueError(

diff --git a/control/iosys.py b/control/iosys.py
@@ -8,7 +8,6 @@
 
 import re
 from copy import deepcopy
-from warnings import warn
 
 import numpy as np
 

diff --git a/control/lti.py b/control/lti.py
@@ -7,7 +7,8 @@
 import numpy as np
 import math
 
-from numpy import real, angle, abs
+# todo: override built-in abs
+from numpy import real, abs
 from warnings import warn
 from . import config
 from .iosys import InputOutputSystem

diff --git a/control/margins.py b/control/margins.py
@@ -52,7 +52,6 @@
 import numpy as np
 import scipy as sp
 from . import xferfcn
-from .lti import evalfr
 from .iosys import issiso
 from . import frdata
 from . import freqplot

diff --git a/control/mateqn.py b/control/mateqn.py
@@ -37,7 +37,7 @@
 
 import warnings
 import numpy as np
-from numpy import copy, eye, dot, finfo, inexact, atleast_2d
+from numpy import eye, finfo, inexact
 
 import scipy as sp
 from scipy.linalg import eigvals, solve

diff --git a/control/matlab/__init__.py b/control/matlab/__init__.py
@@ -50,6 +50,9 @@
 
 """
 
+# Silence unused imports (F401), * imports (F403), unknown symbols (F405)
+# ruff: noqa: F401, F403, F405
+
 # Import MATLAB-like functions that are defined in other packages
 from scipy.signal import zpk2ss, ss2zpk, tf2zpk, zpk2tf
 from numpy import linspace, logspace

diff --git a/control/modelsimp.py b/control/modelsimp.py
@@ -340,7 +340,7 @@ def balanced_reduction(sys, orders, method='truncate', alpha=None):
 
     # check if orders is a list or a scalar
     try:
-        order = iter(orders)
+        iter(orders)
     except TypeError:           # if orders is a scalar
         orders = [orders]
 

diff --git a/control/nichols.py b/control/nichols.py
@@ -21,7 +21,6 @@
 from .ctrlplot import ControlPlot, _get_line_labels, _process_ax_keyword, \
     _process_legend_keywords, _process_line_labels, _update_plot_title
 from .ctrlutil import unwrap
-from .freqplot import _default_frequency_range, _freqplot_defaults
 from .lti import frequency_response
 from .statesp import StateSpace
 from .xferfcn import TransferFunction
@@ -137,7 +136,7 @@ def nichols_plot(
 
         # Decide on the system name and label
         sysname = response.sysname if response.sysname is not None \
-            else f"Unknown-{idx_sys}"
+            else f"Unknown-sys_{idx}"
         label_ = sysname if label is None else label[idx]
 
         # Generate the plot

diff --git a/control/nlsys.py b/control/nlsys.py
@@ -18,15 +18,14 @@
 
 """
 
-import copy
 from warnings import warn
 
 import numpy as np
 import scipy as sp
 
 from . import config
 from .iosys import InputOutputSystem, _parse_spec, _process_iosys_keywords, \
-    _process_signal_list, common_timebase, iosys_repr, isctime, isdtime
+    common_timebase, iosys_repr, isctime, isdtime
 from .timeresp import _check_convert_array, _process_time_response, \
     TimeResponseData, TimeResponseList
 
@@ -211,7 +210,7 @@ def __mul__(self, other):
                 "can't multiply systems with incompatible inputs and outputs")
 
         # Make sure timebase are compatible
-        dt = common_timebase(other.dt, self.dt)
+        common_timebase(other.dt, self.dt)
 
         # Create a new system to handle the composition
         inplist = [(0, i) for i in range(other.ninputs)]
@@ -243,7 +242,7 @@ def __rmul__(self, other):
                              "inputs and outputs")
 
         # Make sure timebase are compatible
-        dt = common_timebase(self.dt, other.dt)
+        common_timebase(self.dt, other.dt)
 
         # Create a new system to handle the composition
         inplist = [(0, i) for i in range(self.ninputs)]
@@ -811,7 +810,7 @@ def cxn_string(signal, gain, first):
                 return (" - " if not first else "-") + \
                     f"{abs(gain)} * {signal}"
 
-        out += f"\nConnections:\n"
+        out += "\nConnections:\n"
         for i in range(len(input_list)):
             first = True
             cxn = f"{input_list[i]} <- "
@@ -831,7 +830,7 @@ def cxn_string(signal, gain, first):
                 cxn, width=78, initial_indent=" * ",
                 subsequent_indent="     ")) + "\n"
 
-        out += f"\nOutputs:\n"
+        out += "\nOutputs:\n"
         for i in range(len(self.output_labels)):
             first = True
             cxn = f"{self.output_labels[i]} <- "
@@ -2474,8 +2473,7 @@ def interconnect(
     `outputs`, for more natural naming of SISO systems.
 
     """
-    from .statesp import LinearICSystem, StateSpace, _convert_to_statespace
-    from .xferfcn import TransferFunction
+    from .statesp import LinearICSystem, StateSpace
 
     dt = kwargs.pop('dt', None)         # bypass normal 'dt' processing
     name, inputs, outputs, states, _ = _process_iosys_keywords(kwargs)
@@ -2537,7 +2535,7 @@ def interconnect(
     # This includes signal lists such as ('sysname', ['sig1', 'sig2', ...])
     # as well as slice-based specifications such as 'sysname.signal[i:j]'.
     #
-    dprint(f"Pre-processing connections:")
+    dprint("Pre-processing connections:")
     new_connections = []
     for connection in connections:
         dprint(f"  parsing {connection=}")
@@ -2576,7 +2574,7 @@ def interconnect(
     #
     dprint(f"Pre-processing input connections: {inplist}")
     if not isinstance(inplist, list):
-        dprint(f"  converting inplist to list")
+        dprint("  converting inplist to list")
         inplist = [inplist]
     new_inplist, new_inputs = [], [] if inplist_none else inputs
 
@@ -2639,7 +2637,7 @@ def interconnect(
         else:
             if isinstance(connection, list):
                 # Passed a list => create input map
-                dprint(f"  detected input list")
+                dprint("  detected input list")
                 signal_list = []
                 for spec in connection:
                     isys, indices, gain = _parse_spec(syslist, spec, 'input')
@@ -2665,7 +2663,7 @@ def interconnect(
     #
     dprint(f"Pre-processing output connections: {outlist}")
     if not isinstance(outlist, list):
-        dprint(f"  converting outlist to list")
+        dprint("  converting outlist to list")
         outlist = [outlist]
     new_outlist, new_outputs = [], [] if outlist_none else outputs
     for iout, connection in enumerate(outlist):
@@ -2742,7 +2740,7 @@ def _find_output_or_input_signal(spec):
 
             if isinstance(connection, list):
                 # Passed a list => create input map
-                dprint(f"  detected output list")
+                dprint("  detected output list")
                 signal_list = []
                 for spec in connection:
                     signal_list += _find_output_or_input_signal(spec)

diff --git a/control/optimal.py b/control/optimal.py
@@ -23,8 +23,7 @@
 import time
 
 from . import config
-from .exception import ControlNotImplemented
-from .iosys import _process_indices, _process_labels, \
+from .iosys import _process_labels, \
     _process_control_disturbance_indices
 
 
@@ -163,7 +162,7 @@ def __init__(
         if trajectory_method is None:
             trajectory_method = 'collocation' if sys.isctime() else 'shooting'
         elif trajectory_method not in _optimal_trajectory_methods:
-            raise NotImplementedError(f"Unkown method {method}")
+            raise NotImplementedError(f"Unknown method {trajectory_method}")
 
         self.shooting = trajectory_method in {'shooting'}
         self.collocation = trajectory_method in {'collocation'}
@@ -1106,7 +1105,7 @@ def solve_ocp(
     # Process (legacy) method keyword
     if kwargs.get('method'):
         method = kwargs.pop('method')
-        if method not in optimal_methods:
+        if method not in _optimal_trajectory_methods:
             if kwargs.get('minimize_method'):
                 raise ValueError("'minimize_method' specified more than once")
             warnings.warn(
-Original file line number
+Diff line change
@@ Expand Up / @@ -48,7 +48,6 @@ @@
     """
     from .iosys import isctime
-    from .statesp import StateSpace
     __all__ = ['sample_system', 'c2d']
@@ Expand Down @@