Remove reserved variables

[eggerdj]

Summary

The variables __drive_freq_parameter__ and __readout_freq_parameter__ have been removed from Calibrations.

Details and comments

• Why this change was necessary: These frequency variables were given special treatment which is inconsistent with the framework. Furthermore, this way of handling variables that do not have a schedule was not scalable.

• What alternative solutions were considered and why the current solution was chosen: To replace them a mechanism to define and add parameters without a schedule has been added to the basis gate library. This has the benefit of making the API of frequency calibration experiments consistent with the other calibration experiments. Furthermore, the proposed change is scalable in that users can add more parameters that do not have a schedule to a library.

• What tests and documentation have been added/updated: A test was added to make sure that users can add parameters.

• What do users and developers need to know about this change: Users can now add parameters to their library that are not attached to a schedule in a meaningful way. The variables __drive_freq_parameter__ and __readout_freq_parameter__ have been removed from Calibrations.

[nkanazawa1989]

Thanks Daniel. I like this change. This will make it easy to define new gate library of, for example, qudit calibration where anharmonicity is necessary in addition to drive_freq. This approach looks good, but I also want to minimize new public attributes to reduce future maintenance overhead.