psana/src/det_interface.py

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from Detector.PyDetector import detector_factory as _detector_factory
import datasource

def _getEnv(local_env=None):
    if local_env is None:
        if datasource._global_env is None:
            raise RuntimeError('Detector object cannot be created before an instance'
                               ' of psana.DataSource exists')
        return datasource._global_env
    else:
        return local_env

def Detector(name, local_env=None, accept_missing=False):
    """
    Create a python Detector from a string identifier.

    Parameters
    ----------
    source_string : str
        A string identifying a piece of data to access, examples include:
          - 'cspad'                  # a DAQ detector alias
          - 'XppGon.0:Cspad.0'       # a DAQ detector full-name
          - 'DIAG:FEE1:202:241:Data' # an EPICS variable name (or alias)
          - 'EBeam'                  # a BldInfo identifier\n
        The idea is that you should be able to pass something that makes
        sense to you as a human here, and you automatically get the right
        detector object in return.

    local_env : psana.Env
        The psana environment object associated with the psana.DataSource
        you are interested in (from method DataSource.env()).

    accept_missing : bool
        If False, KeyError exception will be raised if "name" is not
        present in the current DataSource.  If True, an object will
        be returned that returns None for all method calls.  This allows
        software to not crash if a detector is missing from a run.

    Returns
    -------
    A psana-python detector object. Try detector(psana.Event) to
    access your data.

    HOW TO GET MORE HELP
    --------------------
    The Detector method returns an object that has methods that
    change depending on the detector type. To see help for a particular
    detector type execute commands similar to the following

    env = DataSource('exp=xpptut15:run=54').env()
    det = Detector('cspad',env)

    and then use the standard ipython "det?" command (and tab completion) to
    see the documentation for that particular detector type.
    """
    env = _getEnv(local_env)
    return _detector_factory(name, env, accept_missing=accept_missing)

def _epicsNames(local_env=None):
    env = _getEnv(local_env)
    epics = env.epicsStore()
    # leave a placeholder for "user alias" from the calibdir
    return [(pv, epics.alias(pv),'') for pv in epics.pvNames()]

def _detNames(local_env=None):
    env = _getEnv(local_env)
    amap = env.aliasMap()
    namelist = []
    # leave a placeholder for "user alias" from the calibdir
    for s in amap.srcs():
        if str(s).find('EpicsArch')!=-1: continue
        namelist.append((str(s).split('(')[-1].split(')')[0],amap.alias(s),''))
    cstore = env.configStore()
    for k in cstore.keys():
        if 'ControlData.Config' in str(k.type()):
            namelist.append(('ControlData','',''))
            break
    return namelist

def DetNames(nametype='detectors',local_env=None):
    """
    Return tuples of detector names.  Nametype should be one of
    'detectors','epics','all'.  'detectors' returns the names of all standard
    detectors included in the data.  'epics' returns the names of all epics
    variables (epics variables are typically updated at 1Hz with information
    about slow quantities like temperatures, voltages, motor positions).
    'all' returns both of the above.

    Each detector can have 3 names: a "full name", a simpler "daq alias", or a
    "user alias".  The last two are optional.

    This routine takes an optional "DataSource.Env" argument.  If not provided
    the Env from the most recently created DataSource will be used.  It typically
    only needs to be specified when using multiple DataSource instances simultaneously.
    """
    if nametype=='detectors':
        return _detNames(local_env)
    elif nametype=='epics':
        return _epicsNames(local_env)
    elif nametype=='all':
        return _detNames(local_env)+_epicsNames(local_env)
    else:
        raise ValueError('Name type must be one of "detectors, epics, all"')

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