Omega scans¶
The gwdetchar.omega
module provides a python implementation of the Omega gravitational-wave burst detection pipeline, used extensively for characterisation of transient noise in LIGO. This pipeline is designed around the Q-transform and is used to analyze hundreds of channels.
The omega pipeline provides a ‘scan’ utility to make high-resolution Q-transform spectrograms of a configurable group of channels, to study the morphology and source of specific transient events (glitches).
The gwdetchar.omega
module provides the following functions:
|
High-pass a |
|
Whiten a |
|
Condition some input data for an omega scan |
|
Condition the primary channel for use as a matched-filter |
|
Cross-correlate two |
|
Scan a channel for evidence of transients |
The gwdetchar.omega.plot
module also provides functions for plotting omega scan data products:
|
Custom plot for a GWPy TimeSeries object |
|
Custom plot for a GWPy spectrogram or Q-gram |
|
Custom plot utility for a full omega scan |
Command-line utilities¶
GWDetChar provides two command-line utilities for running omega scans, taking care of data discovery and (optionally) configuration discovery for you.
Note
For users working on any of the LIGO Data Grid (LDG) computer clusters, a standard set of configuration files are maintained and discoverable by default with gwdetchar.omega
. For information about how to write custom configuration files, see the gwdetchar.omega.config
module.
gwdetchar.omega¶
The gwdetchar.omega
command-line interface is a Q-transform utility for generating omega scans. The simplest usage is as follows:
python -m gwdetchar.omega -i `<interferometer>` `<gps-time>`
For example,
python -m gwdetchar.omega -i L1 1126259461.5
For a full explanation of the available command-line arguments and options, you can run
$ python -m gwdetchar.omega --help
usage: python -m gwdetchar.omega [-h] [-V] [-i IFO] [-o OUTPUT_DIRECTORY]
[-f CONFIG_FILE] [-d] [-D] [-s]
[-t FAR_THRESHOLD] [-y FREQUENCY_SCALING]
[-c COLORMAP] [-j NPROC]
gpstime
Produce an Omega scan for a list of channels around a given GPS time
This utility can be used to process an arbitrary list of detector channels
with minimal effort in finding data. The input should be an INI-formatted
configuration file that lists processing options and channels in contextual
blocks. For more information, see gwdetchar.omega.config.
positional arguments:
gpstime GPS time or datestring to scan
options:
-h, --help show this help message and exit
-V, --version show program's version number and exit
-i IFO, --ifo IFO IFO prefix for this analysis, default: None
-o OUTPUT_DIRECTORY, --output-directory OUTPUT_DIRECTORY
output directory for the Omega scan, default:
~/public_html/wdq/{IFO}_{gpstime}
-f CONFIG_FILE, --config-file CONFIG_FILE
path to configuration file to use, can be given
multiple times (files read in order), default: choose
a standard one based on IFO and GPS time
-d, --disable-correlation
disable cross-correlation of aux channels, default:
False
-D, --disable-checkpoint
disable checkpointing from previous runs, default:
False
-s, --ignore-state-flags
ignore state flag definitions in the configuration,
default: False
-t FAR_THRESHOLD, --far-threshold FAR_THRESHOLD
white noise false alarm rate threshold (Hz) for
processing channels, default: 3.171e-08
-y FREQUENCY_SCALING, --frequency-scaling FREQUENCY_SCALING
scaling of all frequency axes, default: log
-c COLORMAP, --colormap COLORMAP
name of colormap to use, default: viridis
-j NPROC, --nproc NPROC
the number of processes to use when reading data,
default: 8
gwdetchar.omega.batch¶
To enable batch processing, gwdetchar.omega.batch
is a wrapper around gwdetchar.omega
that builds a workflow for executing multiple omega scans at once. This tool will generate a Condor workflow (a Directed Acyclic Graph, or DAG) to process multiple event times either in parallel or in series.
The simplest usage is much the same as for gwdetchar.omega
, but with multiple times:
python -m gwdetchar.omega.batch -i `<interferometer>` `<gps-time-1>` `<gps-time-2>` `<gps-time-3>` `...`
Alternatively, you can pass all of the times in a single file:
python -m gwdetchar.omega.batch -i L1 mytimes.txt
where mytimes.txt
should contain a single column of GPS times.
For a full explanation of the available command-line interface and options, you can run
$ python -m gwdetchar.omega.batch --help
usage: python -m gwdetchar.omega.batch [-h] [-V] -i IFO [-o OUTPUT_DIR]
[-f CONFIG_FILE] [-d] [-D] [-s]
[-t FAR_THRESHOLD]
[-y FREQUENCY_SCALING] [-c COLORMAP]
[-j NPROC] [-u UNIVERSE] [--submit]
[--monitor]
[--condor-accounting-group CONDOR_ACCOUNTING_GROUP]
[--condor-accounting-group-user CONDOR_ACCOUNTING_GROUP_USER]
[--condor-timeout T]
[--condor-command CONDOR_COMMAND]
gpstime [gpstime ...]
Batch-generate a series of Omega scans
GPS times can be given individually on the command-line, one after the other,
or can be bundled into one file formatted where the first column contains
the GPS times (other columns are ignored).
The output of this script is a condor workflow in the form of a DAG file,
with associated condor submit (`.sub`) file in the output directory.
Submitting the workflow to Condor will result in the scans being processed
in parallel.
positional arguments:
gpstime GPS time(s) to scan, or path to a filecontaining a
single column of such times
options:
-h, --help show this help message and exit
-V, --version show program's version number and exit
-i IFO, --ifo IFO IFO prefix for this analysis, default: None
-o OUTPUT_DIR, --output-dir OUTPUT_DIR
output directory for all scans, default: /home/docs/ch
eckouts/readthedocs.org/user_builds/gwdetchar/checkout
s/latest/docs
Omega scan options:
-f CONFIG_FILE, --config-file CONFIG_FILE
path to configuration file to use, default: choose
based on observatory, epoch, and pipeline
-d, --disable-correlation
disable cross-correlation of aux channels, default:
False
-D, --disable-checkpoint
disable checkpointing from previous runs, default:
False
-s, --ignore-state-flags
ignore state flag definitions in the configuration,
default: False
-t FAR_THRESHOLD, --far-threshold FAR_THRESHOLD
white noise false alarm rate threshold (Hz) for
processing channels, default: 3.171e-08
-y FREQUENCY_SCALING, --frequency-scaling FREQUENCY_SCALING
scaling of all frequency axes, default: log
-c COLORMAP, --colormap COLORMAP
name of colormap to use, default: viridis
-j NPROC, --nproc NPROC
the number of processes to use when reading data,
default: 8
Condor options:
-u UNIVERSE, --universe UNIVERSE
universe for condor processing
--submit submit DAG directly to condor queue
--monitor monitor the DAG progress after submission; only used
with --submit
--condor-accounting-group CONDOR_ACCOUNTING_GROUP
accounting_group for condor submission on the LIGO
Data Grid, include '{epoch}' (with curly brackets) to
auto-substitute the appropriate epoch based on the GPS
times
--condor-accounting-group-user CONDOR_ACCOUNTING_GROUP_USER
accounting_group_user for condor submission on the
LIGO Data Grid
--condor-timeout T configure condor to terminate jobs after T hours to
prevent idling, default: None
--condor-command CONDOR_COMMAND
Extra condor submit commands to add to gw_summary
submit file. Can be given multiple times in the form
"key=value"