DataQualityDict

class gwpy.segments.DataQualityDict

An OrderedDict of (key, DataQualityFlag) pairs.

Since the DataQualityDict is an OrderedDict, all iterations over its elements retain the order in which they were inserted.

Methods Summary

clear()
coalesce()	Coalesce all segments lists in this DataQualityDict.
copy([deep])	Build a copy of this dictionary.
from_ligolw_tables(segmentdeftable, ...[, ...])	Build a DataQualityDict from a set of LIGO_LW segment tables
from_veto_definer_file(fp[, start, end, ...])	Read a DataQualityDict from a LIGO_LW XML VetoDefinerTable.
fromkeys(/, iterable[, value])	Create a new ordered dictionary with keys from iterable and values set to value.
get(key[, default])	Return the value for key if key is in the dictionary, else default.
intersection()	Return the intersection of all flags in this dict
items()
keys()
move_to_end(/, key[, last])	Move an existing element to the end (or beginning if last is false).
plot([label])	Plot this flag on a segments projection.
pop(k[,d])	value.
popitem(/[, last])	Remove and return a (key, value) pair from the dictionary.
populate([source, segments, pad, on_error])	Query the segment database for each flag's active segments.
query(flags, *args, **kwargs)	Query for segments of a set of flags.
query_dqsegdb(flags, *args, **kwargs)	Query the advanced LIGO DQSegDB for a list of flags.
query_segdb(flags, *args, **kwargs)	Query the inital LIGO segment database for a list of flags.
read(source[, names, format])	Read segments from file into a DataQualityDict
setdefault(/, key[, default])	Insert key with a value of default if key is not in the dictionary.
to_ligolw_tables([ilwdchar_compat])	Convert this DataQualityDict into a trio of LIGO_LW segment tables
union()	Return the union of all flags in this dict
update([E, ]**F)	If E is present and has a .keys() method, then does: for k in E: D[k] = E[k] If E is present and lacks a .keys() method, then does: for k, v in E: D[k] = v In either case, this is followed by: for k in F: D[k] = F[k]
values()
write(target, *args, **kwargs)	Write this DataQualityDict to file

Methods Documentation

clear() → None.  Remove all items from od.

coalesce()

Coalesce all segments lists in this DataQualityDict.

This method modifies this object in-place.

Returns

self

a view of this flag, not a copy.

copy(deep=False)

Build a copy of this dictionary.

Parameters

deep : bool, optional, default: False

perform a deep copy of the original dictionary with a fresh memory address

Returns

flag2 : DataQualityFlag

a copy of the original dictionary

classmethod from_ligolw_tables(segmentdeftable, segmentsumtable, segmenttable, names=None, gpstype=<class 'lal.LIGOTimeGPS'>, on_missing='error')

Build a DataQualityDict from a set of LIGO_LW segment tables

Parameters

segmentdeftable : SegmentDefTable

the segment_definer table to read

segmentsumtable : SegmentSumTable

the segment_summary table to read

segmenttable : SegmentTable

the segment table to read

names : list of str, optional

a list of flag names to read, defaults to returning all

gpstype : type, callable, optional

class to use for GPS times in returned objects, can be a function to convert GPS time to something else, default is LIGOTimeGPS

on_missing : str, optional

action to take when a one or more names are not found in the segment_definer table, one of

• 'ignore' : do nothing

• 'warn' : print a warning

• error' : raise a ValueError

Returns

dqdict : DataQualityDict

a dict of DataQualityFlag objects populated from the LIGO_LW tables

classmethod from_veto_definer_file(fp, start=None, end=None, ifo=None, format='ligolw')

Read a DataQualityDict from a LIGO_LW XML VetoDefinerTable.

Parameters

fp : str

path of veto definer file to read

start : LIGOTimeGPS, int, optional

GPS start time at which to restrict returned flags

end : LIGOTimeGPS, int, optional

GPS end time at which to restrict returned flags

ifo : str, optional

interferometer prefix whose flags you want to read

format : str, optional

format of file to read, currently only ‘ligolw’ is supported

Returns

flags : DataQualityDict

a DataQualityDict of flags parsed from the veto_def_table of the input file.

Notes

This method does not automatically populate the active segment list of any flags, a separate call should be made for that as follows

>>> flags = DataQualityDict.from_veto_definer_file('/path/to/file.xml')
>>> flags.populate()

fromkeys(/, iterable, value=None)

Create a new ordered dictionary with keys from iterable and values set to value.

get(key, default=None, /)

Return the value for key if key is in the dictionary, else default.

intersection()

Return the intersection of all flags in this dict

Returns

intersection : DataQualityFlag

a new DataQualityFlag who’s active and known segments are the intersection of those of the values of this dict

items() → a set-like object providing a view on D's items

keys() → a set-like object providing a view on D's keys

move_to_end(/, key, last=True)

Move an existing element to the end (or beginning if last is false).

Raise KeyError if the element does not exist.

plot(label='key', **kwargs)

Plot this flag on a segments projection.

Parameters

label : str, optional

Labelling system to use, or fixed label for all flags, special values include

• 'key': use the key of the DataQualityDict,

• 'name': use the name of the flag

If anything else, that fixed label will be used for all lines.

**kwargs

all keyword arguments are passed to the Plot constructor.

Returns

figure : Figure

the newly created figure, with populated Axes.

See also

matplotlib.pyplot.figure

for documentation of keyword arguments used to create the figure

matplotlib.figure.Figure.add_subplot

for documentation of keyword arguments used to create the axes

gwpy.plot.SegmentAxes.plot_segmentlist

for documentation of keyword arguments used in rendering the data

pop(k[, d]) → v, remove specified key and return the corresponding

value. If key is not found, d is returned if given, otherwise KeyError is raised.

popitem(/, last=True)

Remove and return a (key, value) pair from the dictionary.

Pairs are returned in LIFO order if last is true or FIFO order if false.

populate(source='http://segments.ldas.cit', segments=None, pad=True, on_error='raise', **kwargs)

Query the segment database for each flag’s active segments.

This method assumes all of the metadata for each flag have been filled. Minimally, the following attributes must be filled

name	The name associated with this flag.
known	The set of segments during which this flag was known, and its state was well defined.

Segments will be fetched from the database, with any padding added on-the-fly.

Entries in this dict will be modified in-place.

Parameters

source : str

source of segments for this flag. This must be either a URL for a segment database or a path to a file on disk.

segments : SegmentList, optional

a list of known segments during which to query, if not given, existing known segments for flags will be used.

pad : bool, optional, default: True

apply the padding associated with each flag, default: True.

on_error : str

how to handle an error querying for one flag, one of

• 'raise' (default): raise the Exception

• 'warn': print a warning

• 'ignore': move onto the next flag as if nothing happened

**kwargs

any other keyword arguments to be passed to DataQualityFlag.query() or DataQualityFlag.read().

Returns

self : DataQualityDict

a reference to the modified DataQualityDict

classmethod query(flags, *args, **kwargs)

Query for segments of a set of flags.

This method intelligently selects the query_segdb or the query_dqsegdb methods based on the url kwarg given.

Parameters

flags : iterable

A list of flag names for which to query.

*args

Either, two float-like numbers indicating the GPS [start, stop) interval, or a SegmentList defining a number of summary segments

url : str, optional

URL of the segment database, defaults to $DEFAULT_SEGMENT_SERVER environment variable, or 'https://segments.ligo.org'

Returns

flagdict : DataQualityDict

A dict of (name, DataQualityFlag) pairs

See also

DataQualityDict.query_segdb

DataQualityDict.query_dqsegdb

for details on the actual query engine, and documentation of other keyword arguments appropriate for each query

classmethod query_dqsegdb(flags, *args, **kwargs)

Query the advanced LIGO DQSegDB for a list of flags.

Parameters

flags : iterable

A list of flag names for which to query.

*args

Either, two float-like numbers indicating the GPS [start, stop) interval, or a SegmentList defining a number of summary segments.

on_error : str

how to handle an error querying for one flag, one of

• 'raise' (default): raise the Exception

• 'warn': print a warning

• 'ignore': move onto the next flag as if nothing happened

url : str, optional

URL of the segment database, defaults to $DEFAULT_SEGMENT_SERVER environment variable, or 'https://segments.ligo.org'

Returns

flagdict : DataQualityDict

An ordered DataQualityDict of (name, DataQualityFlag) pairs.

classmethod query_segdb(flags, *args, **kwargs)

Query the inital LIGO segment database for a list of flags.

Parameters

flags : iterable

A list of flag names for which to query.

*args

Either, two float-like numbers indicating the GPS [start, stop) interval, or a SegmentList defining a number of summary segments.

url : str, optional

URL of the segment database, defaults to $DEFAULT_SEGMENT_SERVER environment variable, or 'https://segments.ligo.org'

Returns

flagdict : DataQualityDict

An ordered DataQualityDict of (name, DataQualityFlag) pairs.

classmethod read(source, names=None, format=None, **kwargs)

Read segments from file into a DataQualityDict

Parameters

source : str

path of file to read

format : str, optional

source format identifier. If not given, the format will be detected if possible. See below for list of acceptable formats.

names : list, optional, default: read all names found

list of names to read, by default all names are read separately.

coalesce : bool, optional

if True coalesce the all segment lists before returning, otherwise return exactly as contained in file(s).

nproc : int, optional, default: 1

number of CPUs to use for parallel reading of multiple files

verbose : bool, optional, default: False

print a progress bar showing read status

Returns

flagdict : DataQualityDict

a new DataQualityDict of DataQualityFlag entries with active and known segments seeded from the XML tables in the given file.

Notes

The available built-in formats are:

Format	Read	Write	Auto-identify
hdf5	Yes	No	No
ligolw	Yes	Yes	Yes

setdefault(/, key, default=None)

Insert key with a value of default if key is not in the dictionary.

Return the value for key if key is in the dictionary, else default.

to_ligolw_tables(ilwdchar_compat=None, **attrs)

Convert this DataQualityDict into a trio of LIGO_LW segment tables

Parameters

ilwdchar_compat : bool, optional

whether to write in the old format, compatible with ILWD characters (True), or to use the new format (False); the current default is True to maintain backwards compatibility, but this will change for gwpy-1.0.0.

**attrs

other attributes to add to all rows in all tables (e.g. 'process_id')

Returns

segmentdeftable : SegmentDefTable

the segment_definer table

segmentsumtable : SegmentSumTable

the segment_summary table

segmenttable : SegmentTable

the segment table

union()

Return the union of all flags in this dict

Returns

union : DataQualityFlag

a new DataQualityFlag who’s active and known segments are the union of those of the values of this dict

update([E, ]**F) → None.  Update D from dict/iterable E and F.

If E is present and has a .keys() method, then does: for k in E: D[k] = E[k] If E is present and lacks a .keys() method, then does: for k, v in E: D[k] = v In either case, this is followed by: for k in F: D[k] = F[k]

values() → an object providing a view on D's values

write(target, *args, **kwargs)

Write this DataQualityDict to file

Notes

The available built-in formats are:

Format	Read	Write	Auto-identify
hdf5	Yes	Yes	No
ligolw	Yes	Yes	Yes