.. currentmodule:: control
The classes listed below are used to represent models of linear time-invariant (LTI) systems. They are usually created from factory functions such as :func:`tf` and :func:`ss`, so the user should normally not need to instantiate these directly.
.. autosummary:: :toctree: generated/ TransferFunction StateSpace FrequencyResponseData InputOutputSystem
Input/output systems are accessed primarily via a set of subclasses that allow for linear, nonlinear, and interconnected elements:
.. autosummary:: :toctree: generated/ InterconnectedSystem LinearICSystem LinearIOSystem NonlinearIOSystem
.. autosummary:: flatsys.BasisFamily flatsys.FlatSystem flatsys.LinearFlatSystem flatsys.PolyFamily flatsys.SystemTrajectory optimal.OptimalControlProblem