.. SPDX-FileCopyrightText: 2022 Dominik Vilsmeier

   SPDX-License-Identifier: GPL-3.0-or-later


Fit parameters
==============

The `parameters`_ module contains various classes which can be used
to specify fit parameters. Besides the quadrupoles, multipoles and gain
error classes, which can also be specified via shorthand arguments for
`Loco`_, there is another class `NumberParameters`_ which allows to declare
any model parameter (variable) as a fit parameter.

.. note::
   In MADX scripts, these variables should be defined separately and then used
   via ``:=`` in order to ensure that their updated values are used during subsequent
   computations.

The module also contains two helper functions which can be used to assign gain errors
to the ORM and Jacobian, respectively:

* `update_orm_with_gain_errors`_
* `update_jacobian_with_gain_errors`_


.. _parameters: ../../api/accinv.parameters.html
.. _Loco: ../../api/accinv.loco.html#accinv.loco.Loco
.. _NumberParameters: ../../api/accinv.parameters.html#accinv.parameters.NumberParameters
.. _update_orm_with_gain_errors: ../../api/accinv.parameters.html#accinv.parameters.update_orm_with_gain_errors
.. _update_jacobian_with_gain_errors: ../../api/accinv.parameters.html#accinv.parameters.update_jacobian_with_gain_errors