Page History

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• Geometry package for psana: psgeom or PSCalib

  • psgeom:
    • Pros:

      • Clean and modern interface

      • Clean and nice coding style

    • Cons:

      • No single true internal geometry representation

      • Main mantainer not working at LCLS (!!!)

      • Comments from MD:
        • duplication of psana geometry code for panels and entire detector - wrong design, for conversion purpose it should inherit from psana geometry, not substitute it.
        • as a result, it does not normally support hierarchal description of sub-detectors, always needs to be updated for new panel geometry which is done much earlier in psana (example epix10ka, jungfrau).
        • there is no guarantee that converter works correctly (multiple issues in the past) because it uses internal engine for pixel geometry which might be different from original psana.
  • PSCalib.GeometryAccess:
    • Based on the content of this page Detector Geometry

    • Pros:

      • True internal representation of the geometry

      • Better integration with the rest of psana

      • Maintained and developed at LCLS (!!!)

    • Cons:

      • Interface is often not very Pythonic (example: vebosity bits) - MD: outdated comment - for lcls2 geometry is changed significantly

      • Documentation could be more accessible - MD: could be, in-line documentation is available and work in psana1, please provide documentation processor for lcls2.

• Proposal: I propose that we make PSCalib the default geometry package for psana

• Geometry Interface improvement proposals (Work in progress):

  • Expose the bit flags in various functions as Python bool flags - NOTE: maybe already fixed in LCLS2. MD: it is matter of style. I like compact and clean style. In critical places of user interface like det.mask we provide methods with explicit specification of parameters.

  • Do not require parameters that are not strictly needed (for clarity) Example: det.daq.image(evt,array=None)   could be det.daq.image(evt) or det.daq.image(array), either with two separate functions or with different behavior depending on the input data. MD: lcls2 method det.daq.image(evt,array=None) does not exist yet. In psana(1) det.image(evt,array=None) evt needs to be passed along with array.

  • Use more descriptive names for some parameters. Examples: oname, oindex, vbase, etc.

  • Make documentation more accessible (use one of the standard for docstrings?) - NOTE: maybe already fixed in LCLS2. MD: please first provide documentation processor for lcls2. 

  • All this can be accomplished with wrappers, without breakage. MD: what is exact purpose for wrapper?

  • I volunteer to do that, of course

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