Segment by Segment - the backend

[JoschD]

This is the Segment-by-Segment algorithm as envisioned by @jaimecp89.
In this state it should contain the same functionality as the SbsPhaseAdvance (#308) branch, but lacks a test, some doc-strings and some cleanup.

Advantages:

• Separated model creation, segment input and segment-by-segment propagation
• Object Oriented:
  • One only needs to add a Propagable object to add a parameter, which can then be just added to the loop.
  • Highly shared functionality between parameters
• Uses the Optics-Measurements TfsCollection
• Allows for Element-Segments as input (see next point)
• Finds BPMs around from model

Caveats: (i.e. breaking backwards compatibility with BB.src SbS)

• Standardized and simplified output names
• Standardized ini_r## and end_r## to r##_ini and r##_end (as all the other parameters)
• Renamed front (or omission of it) to forward and back to backward everywhere
• Some changes in the Model Creation
  • some paths (model-dir)
  • call-logic: see full_run function and post_run function for checks

Todo:

• Move segment_by_segment.py to main folder.
• move the segment_by_segment/matcher and sbs_matcher.py to new branch (accounts for a lot of changed files, make new issue to adapt it to python3)
• remove debug logging
• Add Test (see text from Tobias below)
• Add doc-strings and type-hints
• Test with segment-by-segment GUI from omc3-gui package

---

From Tobias :

I put an example to start testing the sbs on my work public /afs/cern.ch/work/t/tpersson/public/forSBStest_ACdipole/

There are some files also to generate other tracking but the important just to test the SBS are the files in the measured optics such as total_phase_x.tfs etc. You can compare the result to the output in sbs folder there. The starting point used were:

BPM.12L1.B1
BPM.12R1.B1

And the correction used for the sbs is in the file: sbs/corrections_IP1.madx

The modifier used was the opticsfile.22.

This is a good first test but then the error propagation also needs to be checked. For my version I checked this by analyzing files from Beta-Beat.src and then compared it to the OMC3 with the option beta-beat.src “names”.