def make_multi_burst(process_id, coinc_event_id, events, offset_vector):
multiburst = lsctables.MultiBurst()
multiburst.process_id = process_id
multiburst.coinc_event_id = coinc_event_id
# snr = root sum of ms_snr squares
multiburst.snr = math.sqrt(sum(event.ms_snr**2.0 for event in events))
# peak time = ms_snr squared weighted average of peak times (no
# attempt to account for inter-site delays). LIGOTimeGPS objects
# don't like being multiplied by things, so the first event's peak
# time is used as a reference epoch.
t = events[0].peak + offset_vector[events[0].ifo]
multiburst.peak = t + sum(
event.ms_snr**2.0 * float(event.peak + offset_vector[event.ifo] - t)
for event in events) / multiburst.snr**2.0
# duration = ms_snr squared weighted average of durations
multiburst.duration = sum(event.ms_snr**2.0 * event.duration
for event in events) / multiburst.snr**2.0
# central_freq = ms_snr squared weighted average of peak frequencies
multiburst.central_freq = sum(event.ms_snr**2.0 * event.peak_frequency
for event in events) / multiburst.snr**2.0
# bandwidth = ms_snr squared weighted average of bandwidths
multiburst.bandwidth = sum(event.ms_snr**2.0 * event.bandwidth
for event in events) / multiburst.snr**2.0
# confidence = minimum of confidences
multiburst.confidence = min(event.confidence for event in events)
# "amplitude" = h_rss of event with highest confidence
multiburst.amplitude = max(
(event.ms_confidence, event.ms_hrss) for event in events)[1]
# populate the false alarm rate with none.
multiburst.false_alarm_rate = None
# done
return multiburst
def root_multi_trigger(root_event, columns=CWB_MULTI_COLUMNS):
"""Parse a multi-detector Coherent WaveBurst `ROOT` tree entry
into a `MultiBurst` object.
@param root_event
`ROOT` `TChain` object
@param columns
a list of valid `LIGO_LW` column names to load (defaults to all)
@returns a `MultiBurst` built from the `ROOT` data
"""
ifos = get_ifos(root_event)
first_ifo_idx = CWB_DETECTOR_INDEX.index(list(ifos)[0])
mb = lsctables.MultiBurst()
if 'process_id' in columns:
mb.process_id = lsctables.ProcessID(root_event.run)
if 'event_id' in columns:
mb.event_id = lsctables.MultiBurstTable.get_next_id()
if 'ifos' in columns:
mb.set_ifos(ifos)
peak_time = LIGOTimeGPS(list(root_event.time)[first_ifo_idx])
if 'peak_time' in columns:
mb.peak_time = peak_time.gpsSeconds
if 'peak_time_ns' in columns:
mb.peak_time_ns = peak_time.gpsNanoSeconds
start_time = LIGOTimeGPS(list(root_event.start)[first_ifo_idx])
if 'start_time' in columns:
mb.start_time = start_time.gpsSeconds
if 'start_time_ns' in columns:
mb.start_time_ns = start_time.gpsNanoSeconds
if 'duration' in columns:
mb.duration = float(list(root_event.duration)[first_ifo_idx])
fmin = min(root_event.low)
fmax = min(root_event.high)
if 'central_freq' in columns:
mb.central_freq = list(root_event.frequency)[0]
if 'bandwidth' in columns:
mb.bandwidth = fmax - fmin
if 'snr' in columns:
mb.snr = min(root_event.rho)
if 'confidence' in columns:
mb.confidence = root_event.likelihood
return mb