.. currentmodule:: control

The python-control package can be customized to allow for different default values for selected parameters. This includes the ability to change the way system names are created, to set the style for various types of plots, and to determine default solvers and parameters to use in solving optimization problems.

To set the default value of a configuration parameter, set the appropriate element of the config.defaults dictionary:

ct.config.defaults['module.parameter'] = value

The :func:`set_defaults` function can also be used to set multiple configuration parameters at the same time:

ct.set_defaults('module', param1=val1, param2=val2, ...]

Several functions available to set collections of parameters based on standard configurations:

.. autosummary::

   reset_defaults
   use_fbs_defaults
   use_matlab_defaults
   use_legacy_defaults

.. currentmodule:: control.config.defaults

Finally, the config.defaults object can be used as a context manager for temporarily setting default parameters:

.. testsetup::

   import control as ct

>>> with ct.config.defaults({'iosys.repr_format': 'info'}):
...     sys = ct.rss(4, 2, 2, name='sys')
...     print(repr(sys))
<StateSpace sys: ['u[0]', 'u[1]'] -> ['y[0]', 'y[1]']>

.. py:data:: control.default_dt
   :type: int
   :value: 0

   Default value of `dt` when constructing new I/O systems.  If `dt`
   is not specified explicitly this value will be used.  Set to None
   to leave the timebase unspecified, 0 for continuous-time systems,
   True for discrete-time systems.

.. py:data:: iosys.converted_system_name_prefix
   :type: str
   :value: ''

   Prefix to add to system name when converting a system from one
   representation to another.

.. py:data:: iosys.converted_system_name_suffix
   :type: str
   :value: '$converted'

   Suffix to add to system name when converting a system from one
   representation to another.

.. py:data:: iosys.duplicate_system_name_prefix
   :type: str
   :value: ''

   Prefix to add to system name when making a copy of a system.

.. py:data:: iosys.duplicate_system_name_suffix
   :type: str
   :value: '$copy'

   Suffix to add to system name when making a copy of a system.

.. py:data:: iosys.indexed_system_name_prefix
   :type: str
   :value: ''

   Prefix to add to system name when extracting a subset of the inputs
   and outputs.

.. py:data:: iosys.indexed_system_name_suffix
   :type: str
   :value: '$indexed'

   Suffix to add to system name when extracting a subset of the inputs
   and outputs.

.. py:data:: iosys.linearized_system_name_prefix
   :type: str
   :value: ''

   Prefix to add to system name when linearizing a system using
   :func:`linearize`.

.. py:data:: iosys.linearized_system_name_suffix
   :type: str
   :value: '$linearized'

   Suffix to add to system name when linearizing a system using
   :func:`linearize`.

.. py:data:: iosys.sampled_system_name_prefix
   :type: str
   :value: ''

   Prefix to add to system name when sampling a system at a set of
   frequency points in :func:`frd` or converting a continuous-time
   system to discrete time in :func:`sample_system`.

.. py:data:: iosys.sampled_system_name_suffix
   :type: str
   :value: '$sampled'

   Suffix to add to system name when sampling a system at a set of
   frequency points in :func:`frd` or converting a continuous-time
   system to discrete time in :func:`sample_system`.

.. py:data:: iosys.state_name_delim
   :type: str
   :value: '_'

   Used by :func:`interconnect` to set the names of the states of the
   interconnected system. If the state names are not explicitly given,
   the states will be given names of the form
   '<subsys_name><delim><state_name>', for each subsys in syslist and
   each state_name of each subsys, where <delim> is the value of
   config.defaults['iosys.state_name_delim'].

.. py:data:: statesp.remove_useless_states
   :type: bool
   :value: False

   When creating a :class:`StateSpace` system, remove states that have no
   effect on the input-output dynamics of the system.

.. py:data:: iosys.repr_format
   :type: str
   :value: 'eval'

   Set the default format used by :func:`iosys_repr` to create the
   representation of an :class:`InputOutputSystem`:

     * 'info' : <IOSystemType sysname: [inputs] -> [outputs]>
     * 'eval' : system specific, loadable representation
     * 'latex' : latex representation of the object

.. py:data:: iosys.repr_show_count
   :type: bool
   :value: True

   If True, show the input, output, and state count when using
   `iosys_repr` and the 'eval' format.  Otherwise, the input,
   output, and state values are repressed from the output unless
   non-generic signal names are present.

.. py:data:: xferfcn.display_format
   :type: str
   :value: 'poly'

   Set the display format used in printing the
   :class:`TransferFunction` object:

     * 'poly': Single polynomial for numerator and denominator.
     * 'zpk': Product of factors, showing poles and zeros.

.. py:data:: xferfcn.floating_point_format
   :type: str
   :value: '.4g'

   Format to use for displaying coefficients in
   :class:`TransferFunction` objects when generating string
   representations.

.. py:data:: statesp.latex_num_format
   :type: str
   :value: '.3g'

   Format to use for displaying coefficients in :class:`StateSpace` systems
   when generating LaTeX representations.

.. py:data:: statesp.latex_repr_type
   :type: str
   :value: 'partitioned'

   Used when generating LaTeX representations of :class:`StateSpace`
   systems.  If 'partitioned', the A, B, C, D matrices are shown as
   a single, partitioned matrix; if 'separate', the matrices are
   shown separately.

.. py:data:: statesp.latex_maxsize
   :type: int
   :value: 10

   Maximum number of states plus inputs or outputs for which the LaTeX
   representation of the system dynamics will be generated.

.. py:data:: control.squeeze_frequency_response
   :type: bool
   :value: None

   Set the default value of the `squeeze` parameter for
   :func:`frequency_response` and :class:`FrequencyResponseData`
   objects. If None then if a system is single-input, single-output
   (SISO) the outputs (and inputs) are returned as a 1D array (indexed by
   frequency), and if a system is multi-input or multi-output, then the
   outputs are returned as a 2D array (indexed by output and frequency) or
   a 3D array (indexed by output, input (or trace), and frequency).  If
   `squeeze=True`, access to the output response will remove
   single-dimensional entries from the shape of the inputs and outputs even
   if the system is not SISO. If `squeeze=False`, the output is returned as
   a 3D array (indexed by the output, input, and frequency) even if the
   system is SISO.

.. py:data:: control.squeeze_time_response
   :type: bool
   :value: None

   Set the default value of the `squeeze` parameter for
   :func:`input_output_response` and other time response objects. By
   default, if a system is single-input, single-output (SISO) then the
   outputs (and inputs) are returned as a 1D array (indexed by time) and if
   a system is multi-input or multi-output, then the outputs are returned
   as a 2D array (indexed by output and time) or a 3D array (indexed by
   output, input, and time).  If `squeeze=True`, access to the output
   response will remove single-dimensional entries from the shape of the
   inputs and outputs even if the system is not SISO. If `squeeze=False`,
   the output is returned as a 3D array (indexed by the output, input, and
   time) even if the system is SISO.

.. py:data:: forced_response.return_x
   :type: bool
   :value: False

   Determine whether :func:`forced_response` returns the values of the
   states when the :class:`TimeResponseData` object is evaluated.  The
   default value was True before version 0.9 and is False since then.

.. py:data:: ctrlplot.rcParams
   :type: dict
   :value: {'axes.labelsize': 'small', 'axes.titlesize': 'small', 'figure.titlesize': 'medium', 'legend.fontsize': 'x-small', 'xtick.labelsize': 'small', 'ytick.labelsize': 'small'}

   Overrides the default matplotlib parameters used for generating
   plots.  This dictionary can also be accessed as `ct.rcParams`.

.. py:data:: freqplot.dB
   :type: bool
   :value: False

   If True, the magnitude in :func:`bode_plot` is plotted in dB
   (otherwise powers of 10).

.. py:data:: freqplot.deg
   :type: bool
   :value: True

   If True, the phase in :func:`bode_plot` is plotted in degrees
   (otherwise radians).

.. py:data:: freqplot.feature_periphery_decades
   :type: int
   :value: 1

   Number of decades in frequency to include on both sides of features
   (poles, zeros) when generating frequency plots.

.. py:data:: freqplot.freq_label
   :type: bool
   :value: 'Frequency [{units}]'

   Label for the frequency axis in frequency plots, with `units` set to
   either 'rad/sec' or 'Hz' when the label is created.

.. py:data:: freqplot.grid
   :type: bool
   :value: True

   Include grids for magnitude and phase in frequency plots.

.. py:data:: freqplot.Hz
   :type: bool
   :value: False

   If True, use Hertz for frequency response plots (otherwise rad/sec).

.. py:data:: freqplot.magnitude_label
   :type: str
   :value: 'Magnitude'

   Label to use on the magnitude portion of a frequency plot.  Set to
   'Gain' by `use_fbs_defaults()`.

.. py:data:: freqplot.number_of_samples
   :type: int
   :value: 1000

   Number of frequency points to use in in frequency plots.

.. py:data:: freqplot.share_magnitude
   :type: str
   :value: 'row'

   Determine whether and how axis limits are shared between the magnitude
   variables in :func:`bode_plot`.  Can be set set to 'row' to share across
   all subplots in a row, 'col' to set across all subplots in a column, or
   False to allow independent limits.

.. py:data:: freqplot.share_phase
   :type: str
   :value: 'row'

   Determine whether and how axis limits are shared between the phase
   variables in :func:`bode_plot`.  Can be set set to 'row' to share across
   all subplots in a row, 'col' to set across all subplots in a column, or
   False to allow independent limits.

.. py:data:: freqplot.share_frequency
   :type: str
   :value: 'col'

   Determine whether and how axis limits are shared between the frequency
   axes in :func:`bode_plot`.  Can be set set to 'row' to share across all
   subplots in a row, 'col' to set across all subplots in a column, or
   False to allow independent limits.

.. py:data:: freqplot.title_frame
   :type: str
   :value: 'axes'

   Set the frame of reference used to center the plot title. If set to
   'axes', the horizontal position of the title will be centered relative
   to the axes.  If set to 'figure', it will be centered with respect to
   the figure (faster execution).

.. py:data:: freqplot.wrap_phase
   :type: bool
   :value: False

   If `wrap_phase` is False, then the phase will be unwrapped so that it
   is continuously increasing or decreasing.  If `wrap_phase` is True the
   phase will be restricted to the range [-180, 180) (or [:math:`-\pi`,
   :math:`\pi`) radians). If ``wrap_phase`` is specified as a float, the
   phase will be offset by 360 degrees if it falls below the specified
   value.

.. py:data:: nichols.grid
   :type: bool
   :value: True

   Set to True if :func:`nichols_plot` should include a Nichols-chart
   grid.

.. py:data:: nyquist.arrows
   :type: int
   :value: 2

   Specify the default number of arrows for :func:`nyquist_plot`.

.. py:data:: nyquist.arrow_size
   :type: float
   :value: 8

   Arrowhead width and length (in display coordinates) for
   :func:`nyquist_plot`.

.. py:data:: nyquist.circle_style
   :type: dict
   :value: {'color': 'black', 'linestyle': 'dashed', 'linewidth': 1}

   Style for unit circle in :func:`nyquist_plot`.

.. py:data:: nyquist.encirclement_threshold
   :type: float
   :value: 0.05

   Define the threshold in :func:`nyquist_response` for generating a
   warning if the number of net encirclements is a non-integer value.

.. py:data:: nyquist.indent_direction
   :type: str
   :value: 'right'

   Set the direction of indentation in :func:`nyquist_response` for poles
   on the imaginary axis.  Valid values are 'right', 'left', or 'none'.

.. py:data:: nyquist.indent_points
   :type: int
   :value: 50

   Set the number of points to insert in the Nyquist contour around poles
   that are at or near the imaginary axis in :func:`nyquist_response`.

.. py:data:: nyquist.indent_radius
   :type: float
   :value: 0.0001

   Amount to indent the Nyquist contour around poles on or near the
   imaginary axis in :func:`nyquist_response`. Portions of the Nyquist plot
   corresponding to indented portions of the contour are plotted using a
   different line style.

.. py:data:: nyquist.max_curve_magnitude
   :type: float
   :value: 20

   Restrict the maximum magnitude of the Nyquist plot in
   :func:`nyquist_plot`.  Portions of the Nyquist plot whose magnitude is
   restricted are plotted using a different line style.

.. py:data:: nyquist.max_curve_offset
   :type: float
   :value: 0.02

   When plotting scaled portion of the Nyquist plot in
   :func:`nyquist_plot`, increase/decrease the magnitude by this fraction
   of the `max_curve_magnitude` to allow any overlaps between the primary and
   mirror curves to be avoided.

.. py:data:: nyquist.mirror_style
   :type: list of str
   :value: ['--', ':']

   Linestyles for mirror image of the Nyquist curve in
   :func:`nyquist_plot`.  The first element is used for unscaled
   portions of the Nyquist curve, the second element is used for
   portions that are scaled (using `max_curve_magnitude`).  If False
   then omit the mirror image curve completely.

.. py:data:: nyquist.primary_style
   :type: list of str
   :value: ['-', '-.']

   Linestyles for primary image of the Nyquist curve in
   :func:`nyquist_plot`.  The first element is used for unscaled portions
   of the Nyquist curve, the second element is used for portions that are
   scaled (using max_curve_magnitude).

.. py:data:: nyquist.start_marker
   :type: str
   :value: 'o'

   Matplotlib marker to use to mark the starting point of the Nyquist plot
   in :func:`nyquist_plot`.

.. py:data:: nyquist.start_marker_size
   :type: float
   :value: 4

   Start marker size (in display coordinates) in :func:`nyquist_plot`.

.. py:data:: phaseplot.arrows
   :type: int
   :value: 2

   Set the default number of arrows in :func:`phase_plane_plot` and
   :func:`phaseplot.streamlines`.

.. py:data:: phaseplot.arrow_size
   :type: float
   :value: 8

   Set the default size of arrows in :func:`phase_plane_plot` and
   :func:`phaseplot.streamlines`.

.. py:data:: phaseplot.arrow_style
   :type: matplotlib patch
   :value: None

   Set the default style for arrows in :func:`phase_plane_plot` and
   :func:`phaseplot.streamlines`.  If set to None, defaults to

   .. code::

      mpl.patches.ArrowStyle(
          'simple', head_width=int(2 * arrow_size / 3),
          head_length=arrow_size)

.. py:data:: phaseplot.separatrices_radius
   :type: float
   :value: 0.1

   In :func:`phaseplot.separatrices`, set the offset from the equilibrium
   point to the starting point of the separatix traces, in the direction of
   the eigenvectors evaluated at that equilibrium point.

.. py:data:: pzmap.buffer_factor
   :type: float
   :value: 1.05

   The limits of the pole/zero plot generated by :func:`pole_zero_plot`
   are set based on the location features in the plot, including the
   location of poles, zeros, and local maxima of root locus curves.  The
   locations of local maxima are expanded by the buffer factor set by
   `buffer_factor`.

.. py:data:: pzmap.expansion_factor
   :type: float
   :value: 1.8

   The final axis limits of the pole/zero plot generated by
   :func:`pole_zero_plot` are set to by the largest features in the plot
   multiplied by an expansion factor set by `expansion_factor`.

.. py:data:: pzmap.grid
   :type: bool
   :value: False

   If True plot omega-damping grid in :func:`pole_zero_plot`. If False
   or None show imaginary axis for continuous-time systems, unit circle for
   discrete-time systems.  If 'empty', do not draw any additional lines.

   Note: this setting only applies to pole/zero plots.  For root locus
   plots, the 'rlocus.grid' parameter value is used as the default.

.. py:data:: pzmap.marker_size
   :type: float
   :value: 6

   Set the size of the markers used for poles and zeros in
   :func:`pole_zero_plot`.

.. py:data:: pzmap.marker_width
   :type: float
   :value: 1.5

   Set the line width of the markers used for poles and zeros in
   :func:`pole_zero_plot`.

.. py:data:: rlocus.grid
   :type: bool
   :value: True

   If True, plot omega-damping grid in :func:`root_locus_plot`. If False
   or None show imaginary axis for continuous-time systems, unit circle for
   discrete-time systems.  If 'empty', do not draw any additional lines.

.. py:data:: sisotool.initial_gain
   :type: float
   :value: 1

   Initial gain to use for plotting root locus in :func:`sisotool`.

.. py:data:: timeplot.input_props
   :type: list of dict
   :value: [{'color': 'tab:red'}, {'color': 'tab:purple'}, {'color': 'tab:brown'},  {'color': 'tab:olive'}, {'color': 'tab:cyan'}]

   List of line properties to use when plotting combined inputs in
   :func:`time_response_plot`.  The line properties for each input will be
   cycled through this list.

.. py:data:: timeplot.output_props
   :type: list of dict
   :value: [{'color': 'tab:blue'}, {'color': 'tab:orange'}, {'color': 'tab:green'}, {'color': 'tab:pink'}, {'color': 'tab:gray'}]

   List of line properties to use when plotting combined outputs in
   :func:`time_response_plot`.  The line properties for each input will be
   cycled through this list.

.. py:data:: timeplot.trace_props
   :type: list of dict
   :value: [{'linestyle': '-'}, {'linestyle': '--'}, {'linestyle': ':'}, {'linestyle': '-.'}]

   List of line properties to use when plotting multiple traces in
   :func:`time_response_plot`.  The line properties for each input will be
   cycled through this list.

.. py:data:: timeplot.sharex
   :type: str
   :value: 'col'

   Determine whether and how x-axis limits are shared between subplots in
   :func:`time_response_plot`.  Can be set set to 'row' to share across all
   subplots in a row, 'col' to set across all subplots in a column, 'all'
   to share across all subplots, or False to allow independent limits.

.. py:data:: timeplot.sharey
   :type: bool
   :value: False

   Determine whether and how y-axis limits are shared between subplots in
   :func:`time_response_plot`.  Can be set set to 'row' to share across all
   subplots in a row, 'col' to set across all subplots in a column, 'all'
   to share across all subplots, or False to allow independent limits.

.. py:data:: timeplot.time_label
   :type: str
   :value: 'Time [s]'

   Label to use for the time axis in :func:`time_response_plot`.

.. py:data:: optimal.minimize_method
   :type: str
   :value: None

   Set the method used by :func:`scipy.optimize.minimize` when called in
   :func:`solve_optimal_trajectory` and :func:`solve_optimal_estimate`.

.. py:data:: optimal.minimize_options
   :type: dict
   :value: {}

   Set the value of the options keyword used by
   :func:`scipy.optimize.minimize` when called in
   :func:`solve_optimal_trajectory` and :func:`solve_optimal_estimate`.

.. py:data:: optimal.minimize_kwargs
   :type: dict
   :value: {}

   Set the keyword arguments passed to :func:`scipy.optimize.minimize`
   when called in :func:`solve_optimal_trajectory` and
   :func:`solve_optimal_estimate`.

.. py:data:: optimal.solve_ivp_method
   :type: str
   :value: None

   Set the method used by :func:`scipy.integrate.solve_ivp` when called in
   :func:`solve_optimal_trajectory` and :func:`solve_optimal_estimate`.

.. py:data:: optimal.solve_ivp_options
   :type: dict
   :value: {}

   Set the value of the options keyword used by
   :func:`scipy.integrate.solve_ivp` when called in
   :func:`solve_optimal_trajectory` and :func:`solve_optimal_estimate`.