Page History

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Accessed from psana event with a pattern like:

evt._dgrams[nDgram].detname[nSegment].drpClassName.attr1.attr2...

• detname is defined by the hutch. For example: "xppcspad" or "xpphsd"
• nSegment is an integer, denoting which portion of a larger detector this is (e.g. cspad panel number)
• drpClassName is defined by the DRP segment-level software via the "Alg" parameter to xtcdata/xtcdata/xtc/ShapesData.hh:Names class.  For example: "raw", "fex", "roi1", "roi2"

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In general xtcdata/xtc/ShapesData.hh::Name names should be python compatible containing only A-Z,a-z,0-9,_.  Unfortunately there are exceptions that make general naming conventions difficult to enforce in "attributes" xtcdata/xtc/ShapesData.hh::Name.  Note that python-compatibility is enforced for the "detector name" in the higher-level ShapesData.hh::Names.  The exceptions for "Name:"

• ENUMDICT and ENUMVAL types have special handling that requires a ":".
• Attributes (e.g. attr1, attr2 in evt._dgrams[nDgram].detname[nSegment].drpClassName.attr1.attr2...) are created by adding "." in the names.
• I think if no alias is specified for epics variables then the ugly epics name is used (often having ":", ".", maybe others, but I haven't seen any)
  • feels like we should prevent "." in the xtc name for epics vars, given the fatal error below where "." is incorrectly interpreted as an attribute delimeter
• in the case of step-scans I think the epics variables have no python-compatible alias name. Need to avoid "." here too?

For epics vars with ":" psana handles it correctly by using getattr() for epics vars.  But that character does not work for names that are not epics/enumdict/enumval.

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(ps-4.1.3) psanagpu102:~$ detnames exp=tmoc00118,run=232
Traceback (most recent call last):
  File "/cds/home/c/cpo/git/lcls2/install/bin/detnames", line 11, in <module>
    load_entry_point('psana', 'console_scripts', 'detnames')()
  File "/cds/home/c/cpo/git/lcls2/psana/psana/app/detnames.py", line 71, in detnames
    names = myrun.detinfo.keys()
  File "/cds/home/c/cpo/git/lcls2/psana/psana/psexp/run.py", line 159, in detinfo
    info[(detname,det_xface_name)] = _enumerate_attrs(getattr(self.Detector(detname),det_xface_name))
  File "/cds/home/c/cpo/git/lcls2/psana/psana/psexp/run.py", line 118, in Detector
    setattr(det,drp_class_name,drp_class(det_name, drp_class_name, self.dsparms.configinfo_dict[det_name], self.dsparms.calibconst[det_name], env_store, var_name))
  File "/cds/home/c/cpo/git/lcls2/psana/psana/detector/misc_detectors.py", line 23, in __init__
    values = getattr(names,n).split('\n')
AttributeError: 'container.Container' object has no attribute 'split'
(ps-4.1.3) psanagpu102:~$ 

Proposal:

• all pvnames should have "." replaced with "_" in ShapesData.hh::Name to avoid confusion with hierarchy delimiter.  This should be done by the step-scan software and epicsArch.

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•  We should not abort, but epics scans need to support "." but xtc naming does not.  PvaDetector doesn't need it because it already has to provide an xtc-compatible name, I

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• believe.

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• at xtc-level

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• enforce use of python-compatible characters plus ":" (for epics step-scans which have no alias) and "." for attribute hierarchies.  If we support ":" for epics scans, might as well support it for epicsArch as well.