:class:`Input` -- Input Variables
.. currentmodule:: trep
| param system: | An instance of :class:`System` to add the variable to. |
|---|---|
| param name: | A string that uniquely identifies the input variable. |
An :class:`Input` instance represents a single variable in the input vector, u, of a mechanical system. Inputs are used by :class:`Force` to apply non-conservative forcing to the system (e.g, a torque or body wrench)
Input variables are created automatically by implementations of :class:`Force` when needed, so you do not need to create them directly unless defining a new force type. In that case, they should be created using :meth:`Force._create_input()`.
If a name is provided, it can be used to identify and retrieve input variables.
The current value of a single input variable can be accessed directly (:attr:`u`) or through :class:`System` to access all input variables at once (:attr:`System.u`).
Warning
Currently :mod:`trep` does not enforce unique names for input variables. It is recommended to provide a unique name for every :class:`Input` so they can be unambiguously retrieved by :meth:`System.get_input`.
.. attribute:: Input.u The current value of the input.
.. attribute:: Input.system The system that owns this input variable. *(read only)*
.. attribute:: Input.force The force that uses this input variable. *(read only)*
.. attribute:: Input.name The name of this input variable or :data:`None`.
.. attribute:: Input.index The index of the input in :attr:`System.inputs`.