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.
In MADX scripts, these variables should be defined separately and then used
:= in order to ensure that their updated values are used during subsequent
The module also contains two helper functions which can be used to assign gain errors to the ORM and Jacobian, respectively: