"""Process identification subpackage.

Turns recorded experiment data into the process models that tuners
consume.  v1 scope (see ``docs/design/03_tuning_methods.md``, section
"Identification front-ends") is open-loop **step-response** fitting:

``pidtune.identification.step_response``
    :class:`~pidtune.identification.step_response.StepResponseData`
    (the validated input record),
    :class:`~pidtune.identification.step_response.FitMethod`,
    :class:`~pidtune.identification.step_response.FitResult`, and the
    fitting entry points
    :func:`~pidtune.identification.step_response.fit_fopdt` /
    :func:`~pidtune.identification.step_response.fit_sopdt`.

Relay-experiment identification lives with its tuner in
:mod:`pidtune.tuners.relay` because the experiment and the rule are
inseparable there; frequency-domain identification is a post-v1
roadmap item (``docs/design/06_roadmap.md``).

Fitting functions are **API stubs** in this milestone; the data
records and their validation are final.
"""

from __future__ import annotations

from .step_response import (
    FitMethod,
    FitResult,
    StepResponseData,
    fit_fopdt,
    fit_sopdt,
)

__all__ = [
    "StepResponseData",
    "FitMethod",
    "FitResult",
    "fit_fopdt",
    "fit_sopdt",
]