lhcoptics

Python package to build LHC optics.

Usage:

git clone githttps://github.com/rdemaria/lhcoptics.git
cd lhcoptics
pip install -e .
python examples/data/make.py

from lhcoptics import LHCOptics
inj=LHCOptics.from_json("examples/data/opt_inj.json")
inj.set_xsuite_model("examples/data/lhc.json") # set an xsuite model
inj.ir5.plot()

NB: Currently needs github.com/rdemaria/xdeps branch upstream/feature/check_limits.

LHCOptics

An LHCOptics contains data for specifying a full LHC Optics. It contains global params and knobs and a list of LHC sections (ir1, ir2, ... , ir8, a12, a23, ..., a78) that contains strengths, local params and local knobs. The optics can contain a model that allows to compute twiss, plot and rematch the optics.

Methods:

• LHCOptics.set_repository(branch): Create a link or a directory acc-models-lhc in the local directory from gitlab.cern.ch/acc-models/acc-models-lhc if it does not exists. Branch are 2024, hl16 etc. If $HOME/local/acc-models-lhc/branch exists, a symlink to this directory is created, else the a full git clone is done.

• LHCOptics.from_json(filename): Create optics from a json file

• LHCOptics.from_dict(dct): Create optics from a dict containing strengths, paramns and knobs, irs and arcs dict

• LHCOptics.from_madx(filename,model): Create optics from a madx istance by extracting strengths, params and knobs from variables. If model is 'madx' or 'xsuite' it will attach the model to the optics

• LHCOptics.from_madxfile(madxfile): As before, but creating a madx instance from a madx script

LHC section methods

An LHCSection is indentified by name, start, end, strengths, params and knobs. A LHCSection is specialzed in LHC Arcs and LHCIRs.

Methods:

• cls.from_json(filename): Create section from a json file

• cls.from_dict(dct): Create section from a dict containing strengths, paramns and knobs

• cls.from_madxfile(filename): Create section from a madx file

• cls.from_madx(madx): Create section from a madx instance

• to_json(filename): Save section to a json file

• to_dict(): Save section to a dict

• to_madx(filename,dst): Save section to dst which could be str, filename, a madx instance, an open file.

• update_model(): transfer strengths and knobs data to parent.model

• update_strength(src): update existing strengths from src.strengths, or src or parent.model if src is None

• update_knobs(src): update existing knobs from src.knobs, or src or parent.model if src is None

• update_params(src): update existing params from src.params, or src or parent.model if src is None

• update(src): combine update_strengths, knobs and params.

• get_params(): measure hardcoded parameters from model

• get_params_from_twiss(): measure hardcoded parameters from a twiss table

• set_params(): add or replace hardcoded parameters from model

• twiss(beam,method): get the twiss table table: beam in (1,2), method see specific sections

• plot(beam,method): plot the twiss table: beam in (1,2), method see specific sections

LHCIRs methods

• twiss_from_init(beam): get twiss table from boundary conditions
• twiss_full(beam): get the twiss table from the full optics
• twiss_from_params(beam): get the twiss table with init from params
• set_init(): set the initial conditions

LHCArcs methods

• twiss_init(beam): get twiss init at boundaries of the arc from periodic solution
• twiss_init_cell(beam): get twiss init at boundaries of cell
• twiss_cell(beam): get periodic solution of cell

Code style

Class definitions, camel case alphabetically sorted:

• class variables lower snake case alphabetically sorted
• static methods
• class methods
• init
• other special double underscore methods
• methods starting with verb lower snake case alphabetically sorteddsf