Channel#

class gwpy.detector.Channel(name: str | Self, **params)[source]#

Bases: object

Representation of a gravitational-wave detectory data channel.

Parameters:

namestr, Channel: Name of this Channel (or another Channel itself). If a Channel is given, all other parameters not set explicitly will be copied over.
sample_ratefloat, Quantity, optional: Rate at which data are sampled for this channel, simple floats must be given in Hz.
unitUnit, str, optional: Name of the unit for the data of this channel.
frequency_rangetuple of float: [low, high) spectral frequency range of interest for this channel.
safebool, optional: If True this channel is ‘safe’ to use as a witness of non-gravitational-wave noise in the detector.
dtypenumpy.dtype, optional: Numeric type of data for this channel.
frametypestr, optional: LDAS name for frames that contain this channel.
modelstr, optional: Name of the SIMULINK front-end model that produces this channel.

Notes

The Channel structure implemented here is designed to match the data recorded in the LIGO Channel Information System (https://cis.ligo.org) for which a query interface is provided.

Attributes Summary

`MATCH`
`dtype`	Numeric type for data in this channel.
`frametype`	LDAS type description for frame files containing this channel.
`frequency_range`	Frequency range of interest (Hertz) for this channel.
`ifo`	Interferometer prefix for this channel.
`model`	Name of the SIMULINK front-end model that defines this channel.
`name`	Name of this channel.
`ndsname`	Name of this channel as stored in the NDS database.
`ndstype`	NDS type integer for this channel.
`safe`	Whether this channel is 'safe' to use as a noise witness.
`sample_rate`	Rate of samples (Hertz) for this channel.
`signal`	Instrumental signal for this channel.
`subsystem`	Instrumental sub-system for this channel.
`system`	Instrumental system for this channel.
`texname`	Name of this channel in LaTeX printable format.
`trend`	Trend type for this channel.
`type`	DAQ data type for this channel.
`unit`	Data unit for this channel.
`url`	CIS browser url for this channel.

Methods Summary

`copy`()	Return a copy of this `Channel`.
`find_frametype`(-> str)	Find the containing frametype(s) for this `Channel`.
`from_arrakis`(arrakischannel)	Generate a new channel using an existing `arrakis.Channel`.
`from_nds2`(nds2channel)	Generate a new channel using an existing nds2.channel object.
`parse_channel_name`(name, *[, strict])	Decompose a channel name string into its components.
`query`(name, *[, kerberos])	Query the LIGO Channel Information System for `name`.
`query_nds2`(name[, host, port, connection, type])	Query an NDS server for channel information.

Attributes Documentation

MATCH = re.compile('((?:(?P<ifo>[A-Z]\\d))?|[\\w-]+):(?:(?P<system>[a-zA-Z0-9]+))?(?:[-_](?P<subsystem>[a-zA-Z0-9]+))?(?:[-_](?P<signal>[a-zA-Z0-9_-]+?))?(?:[\\.-](?P<trend>[a-z]+))?(?:,(?P<type>([a-z]-)?[a-z]+))?$')#

dtype[source]#: Numeric type for data in this channel.

frametype[source]#: LDAS type description for frame files containing this channel.

frequency_range[source]#: Frequency range of interest (Hertz) for this channel.

ifo[source]#: Interferometer prefix for this channel.

model[source]#: Name of the SIMULINK front-end model that defines this channel.

name[source]#

Name of this channel.

This should follow the naming convention, with the following format: ‘IFO:SYSTEM-SUBSYSTEM_SIGNAL’

ndsname[source]#: Name of this channel as stored in the NDS database.

ndstype[source]#

NDS type integer for this channel.

This property is mapped to the Channel.type string.

safe[source]#

Whether this channel is ‘safe’ to use as a noise witness.

Any channel that records part or all of a GW signal as it interacts with the interferometer is not safe to use as a noise witness

A safe value of None simply indicates that the safety of this channel has not been determined

sample_rate[source]#: Rate of samples (Hertz) for this channel.

signal[source]#: Instrumental signal for this channel.

subsystem[source]#: Instrumental sub-system for this channel.

system[source]#: Instrumental system for this channel.

texname[source]#: Name of this channel in LaTeX printable format.

trend[source]#: Trend type for this channel.

type[source]#

DAQ data type for this channel.

Valid values for this field are restricted to those understood by the NDS2 client sofware, namely:

‘m-trend’, ‘online’, ‘raw’, ‘reduced’, ‘s-trend’, ‘static’, ‘test-pt’

unit[source]#: Data unit for this channel.

url[source]#: CIS browser url for this channel.

Methods Documentation

copy() → Self[source]#: Return a copy of this Channel.

find_frametype(

gpstime: SupportsToGps | None = None,

*,

frametype_match: str | Pattern | None = None,

return_all: Literal[False] = False,

allow_tape: bool = True,

**kwargs,

) → str[source]#

find_frametype(

gpstime: SupportsToGps | None = None,

*,

frametype_match: str | Pattern | None = None,

return_all: Literal[True] = True,

allow_tape: bool = True,

**kwargs,

) → list[str]

Find the containing frametype(s) for this Channel.

Parameters:

gpstimeint, optional: A reference GPS time at which to search for frame files. Default is to search in the latest available data for each discoverable dataset.
frametype_matchstr: A regular expression string to use to down-select from the list of all available datasets.
return_all: `bool`, optional: If True return all matched datasets; if False (default) only the first match is returned
allow_tapebool, default: True: If True (default) include datasets whose files are stored on slow magnetic tape.
kwargs: Other keyword arguments are passed directly to gwpy.io.datafind.find_frametype().

Returns:

frametypestr or list[str]: If return_all=False a single str containing the ‘best’ dataset name. If return_all=True a list of dataset names.

classmethod from_arrakis(arrakischannel: arrakis.Channel) → Self[source]#

Generate a new channel using an existing arrakis.Channel.

Parameters:

arrakischannelarrakis.Channel: The input channel from Arrakis to parse.

Returns:

channelgwpy.detector.Channel: A new Channel.

classmethod from_nds2(nds2channel: nds2.channel) → Self[source]#: Generate a new channel using an existing nds2.channel object.

classmethod parse_channel_name( name: str, *, strict: bool = True, ) → dict[str, str | None][source]#

Decompose a channel name string into its components.

This method parses channels acccording to the LIGO Channel Naming Convention LIGO-T990033.

Parameters:

namestr: Name to parse.
strictbool, optional: If True (default) require exact matching of format, with no surrounding text.

Returns:

matchdict

dict of channel name components with the following keys:

'ifo': the letter-number interferometer prefix
'system': the top-level system name
'subsystem': the second-level sub-system name
'signal': the remaining underscore-delimited signal name
'trend': the trend type
'ndstype': the NDS2 channel suffix

Any optional keys that aren’t found will return a value of None

Raises:

ValueError: if the name cannot be parsed with at least an IFO and SYSTEM

Examples

>>> Channel.parse_channel_name("L1:LSC-DARM_IN1_DQ")
{'ifo': 'L1',
 'ndstype': None,
 'signal': 'IN1_DQ',
 'subsystem': 'DARM',
 'system': 'LSC',
 'trend': None}

>>> Channel.parse_channel_name(
...     "H1:ISI-BS_ST1_SENSCOR_GND_STS_X_BLRMS_100M_300M.rms,m-trend",
... )
{'ifo': 'H1',
 'ndstype': 'm-trend',
 'signal': 'ST1_SENSCOR_GND_STS_X_BLRMS_100M_300M',
 'subsystem': 'BS',
 'system': 'ISI',
 'trend': 'rms'}

classmethod query(name: str, *, kerberos: bool | None = None, **kwargs) → Self[source]#

Query the LIGO Channel Information System for name.

Parameters:

namestr: Name of channel for which to query.
kerberosbool, optional: If True use an existing Kerberos ticket as the authentication credential. Default (None) is to check for credentials and request username and password if none are found.
kwargs: Other keyword arguments are passed directly to ciecplib.get().

Returns:

channelChannel: A new Channel containing all of the attributes set from its entry in the CIS.

Query an NDS server for channel information.

Parameters:

namestr: Name of channel for which to query.
hoststr, optional: Name of NDS2 server.
portint, optional: Port number for NDS2 connection.
connectionnds2.connection: Open connection to use for query.
typestr, int: NDS2 channel type with which to restrict query

Returns:

channelChannel: Channel with metadata retrieved from NDS2 server.

Raises:

ValueError: If multiple channels are found for a given name.

Notes

Warning

One of host or connection is required.