lalpulsar.simulateCW.CWSimulator Class Reference

Detailed Description

Definition at line 92 of file simulateCW.py.

Inherits object.

Public Member Functions
def	__init__ (self, tref, tstart, Tdata, waveform, dt_wf, phi0, psi, alpha, delta, det_name, earth_ephem_file="earth00-40-DE405.dat.gz", sun_ephem_file="sun00-40-DE405.dat.gz", tref_at_det=False, extra_comment=None)
	Initialise a continuous-wave signal simulator. More...
def	get_strain (self, fs, tmin=0, tmax=None, noise_sqrt_Sh=0, noise_seed=None)
	Generate strain time series of a continuous-wave signal in the detector frame. More...
def	get_strain_blocks (self, fs, Tblock, noise_sqrt_Sh=0, noise_seed=None)
	Generate strain time series of a continuous-wave signal in the detector frame, in contiguous blocks. More...
def	write_frame_files (self, fs, Tframe, comment="simCW", out_dir=".", noise_sqrt_Sh=0, noise_seed=None)
	Write frame files [1] containing strain time series of a continuous-wave signal. More...
def	get_sfts (self, fmax, Tsft, noise_sqrt_Sh=0, noise_seed=None, window="rectangular", window_param=0)
	Generate SFTs [2] containing strain time series of a continuous-wave signal. More...
def	write_sft_files (self, fmax, Tsft, comment="simCW", out_dir=".", noise_sqrt_Sh=0, noise_seed=None, window="rectangular", window_param=0)
	Write SFT files [2] containing strain time series of a continuous-wave signal. More...

Constructor & Destructor Documentation

__init__()

def lalpulsar.simulateCW.CWSimulator.__init__	(		self,
			tref,
			tstart,
			Tdata,
			waveform,
			dt_wf,
			phi0,
			psi,
			alpha,
			delta,
			det_name,
			earth_ephem_file = "earth00-40-DE405.dat.gz",
			sun_ephem_file = "sun00-40-DE405.dat.gz",
			tref_at_det = False,
			extra_comment = None
	)

Initialise a continuous-wave signal simulator.

Parameters

tref	reference time of signal phase at Solar System barycentre, in GPS seconds (but see tref_at_det)
tstart	start time of signal, in GPS seconds
Tdata	total duration of signal, in seconds
waveform	function which computes signal phase and amplitudes as functions of time: dphi, aplus, across = waveform(dt), where: dt = time since reference time tref; dphi = phase of signal at time dt relative to reference time tref, in radians; aplus = strain amplitude of plus polarisation at time dt; across = strain amplitude of cross polarisation at time dt
dt_wf	sampling time of the function waveform; this need only be small enough to ensure that dphi, aplus, and across are smoothly interpolated, and does not need to make the desired sampling frequency of the output strain time series
phi0	initial phase of the gravitational-wave signal at tstart, in radians
psi	polarisation angle of the gravitational-wave source, in radians
alpha	right ascension of the gravitational-wave source, in radians
delta	declination of the gravitational-wave source, in radians
det_name	name of the gravitational-wave detector to simulate a response for; e.g. "H1" for LIGO Hanford, "L1" for LIGO Livingston, "V1" for Virgo
earth_ephem_file	name of file to load Earth ephemeris from
sun_ephem_file	name of file to load Sun ephemeris from
tref_at_det	default False; if True, shift reference time tref so that dt = 0 is tref in detector frame instead of Solar System barycentre frame, useful if e.g. one wants to turn on signal only for dt > 0, one can use tref as the turn-on time
extra_comment	additional text to add to comment string in frame/SFT headers (not filenames), e.g. for wrapper script commandlines

Definition at line 123 of file simulateCW.py.

Member Function Documentation

get_strain()

def lalpulsar.simulateCW.CWSimulator.get_strain	(		self,
			fs,
			tmin = 0,
			tmax = None,
			noise_sqrt_Sh = 0,
			noise_seed = None
	)

Generate strain time series of a continuous-wave signal in the detector frame.

Parameters

fs	sampling frequency of strain time series, in Hz
tmin	start time for strain time series, as offsets from self.__tstart
tmax	start time for strain time series, as offsets from self.__tstart
noise_sqrt_Sh	if >0, add Gaussian noise with square-root single-sided power spectral density given by this value, in Hz^(-1/2)
noise_seed	use this seed for the random number generator used to create noise; required if noise_sqrt_Sh >0

Returns

(t, h), where: t = start of time strain time series, in GPS seconds; h = strain time series

Definition at line 255 of file simulateCW.py.

get_strain_blocks()

def lalpulsar.simulateCW.CWSimulator.get_strain_blocks	(		self,
			fs,
			Tblock,
			noise_sqrt_Sh = 0,
			noise_seed = None
	)

Generate strain time series of a continuous-wave signal in the detector frame, in contiguous blocks.

Parameters

fs	sampling frequency of strain time series, in Hz
Tblock	length of each block, in seconds; should divide evenly into Tdata
noise_sqrt_Sh	if >0, add Gaussian noise with square-root single-sided power spectral density given by this value, in Hz^(-1/2)
noise_seed	use this seed for the random number generator used to create noise; if None, generate a random seed using os.urandom()

Returns

(t, h, i, N), where: t = start of time strain time series, in GPS seconds; h = strain time series; i = block index, starting from zero; N = number of blocks

This is a Python generator function and so should be called as follows:

S = CWSimulator(...)
for t, h, i, N in S.get_strain_blocks(...):
    ...

Definition at line 299 of file simulateCW.py.

write_frame_files()

def lalpulsar.simulateCW.CWSimulator.write_frame_files	(		self,
			fs,
			Tframe,
			comment = "simCW",
			out_dir = ".",
			noise_sqrt_Sh = 0,
			noise_seed = None
	)

Write frame files [1] containing strain time series of a continuous-wave signal.

The strain time series is written as double-precision post-processed data (ProcData) channel named <detector>:SIMCW-STRAIN, where <detector> is the 2-character detector prefix (e.g. H1 for LIGO Hanford, L1 for LIGO Livingston, V1 for Virgo).

Parameters

fs	sampling frequency of strain time series, in Hz
Tframe	length of each frame, in seconds; should divide evenly into Tdata
comment	frame file name comment, may only contain A-Z, a-z, 0-9, _, +, # characters
out_dir	output directory to write frame files into
noise_sqrt_Sh	if >0, add Gaussian noise with square-root single-sided power spectral density given by this value, in Hz^(-1/2)
noise_seed	use this seed for the random number generator used to create noise; if None, generate a random seed using os.urandom()

Returns

(file, i, N), where: file = name of frame file just written; i = frame file index, starting from zero; N = number of frame files

This is a Python generator function and so should be called as follows:

S = CWSimulator(...)
for file, i, N in S.write_frame_files(...):
    ...

[1] https://dcc.ligo.org/LIGO-T970130/public

Definition at line 359 of file simulateCW.py.

get_sfts()

def lalpulsar.simulateCW.CWSimulator.get_sfts	(		self,
			fmax,
			Tsft,
			noise_sqrt_Sh = 0,
			noise_seed = None,
			window = "rectangular",
			window_param = 0
	)

Generate SFTs [2] containing strain time series of a continuous-wave signal.

Parameters

fmax	maximum SFT frequency, in Hz
Tsft	length of each SFT, in seconds; should divide evenly into Tdata
noise_sqrt_Sh	if >0, add Gaussian noise with square-root single-sided power spectral density given by this value, in Hz^(-1/2)
noise_seed	use this seed for the random number generator used to create noise; if None, generate a random seed using os.urandom()
window	if not None, window the time series before performing the FFT, using the named window function; see XLALCreateNamedREAL8Window()
window_param	parameter for the window function given by window, if needed

Returns

(sft, i, N), where: sft = SFT; i = SFT file index, starting from zero; N = number of SFTs

This is a Python generator function and so should be called as follows:

S = CWSimulator(...)
for sft, i, N in S.get_sfts(...):
    ...

[2] https://dcc.ligo.org/LIGO-T040164/public

Definition at line 448 of file simulateCW.py.

write_sft_files()

def lalpulsar.simulateCW.CWSimulator.write_sft_files	(		self,
			fmax,
			Tsft,
			comment = "simCW",
			out_dir = ".",
			noise_sqrt_Sh = 0,
			noise_seed = None,
			window = "rectangular",
			window_param = 0
	)

Write SFT files [2] containing strain time series of a continuous-wave signal.

Parameters

fmax	maximum SFT frequency, in Hz
Tsft	length of each SFT, in seconds; should divide evenly into Tdata
comment	SFT file name comment, may only contain A-Z, a-z, 0-9 characters
out_dir	output directory to write SFT files into
noise_sqrt_Sh	if >0, add Gaussian noise with square-root single-sided power spectral density given by this value, in Hz^(-1/2)
noise_seed	use this seed for the random number generator used to create noise; if None, generate a random seed using os.urandom()
window	if not None, window the time series before performing the FFT, using the named window function; see XLALCreateNamedREAL8Window()
window_param	parameter for the window function given by window, if needed

Returns

(file, i, N), where: file = name of SFT file just written; i = SFT file index, starting from zero; N = number of SFT files

This is a Python generator function and so should be called as follows:

S = CWSimulator(...)
for file, i, N in S.write_sft_files(...):
    ...

[2] https://dcc.ligo.org/LIGO-T040164/public

Definition at line 515 of file simulateCW.py.