lalframe.frread Namespace Reference

Functions
def	read_timeseries (source, channel, start=None, duration=None, datatype=None, verbose=False)
	Read a TimeSeries of channel data from a source. More...
def	read_channel_from_stream (stream, channel, start, duration, datatype=None)
	Read the TimeSeries of a single channel from an open stream. More...
def	get_stream_length (stream, channel)
	Find the number of samples represented in a frame stream. More...
def	get_stream_duration (stream)
	Find the duration of time stored in a frame stream. More...

Function Documentation

read_timeseries()

def lalframe.frread.read_timeseries	(		source,
			channel,
			start = None,
			duration = None,
			datatype = None,
			verbose = False
	)

Read a TimeSeries of channel data from a source.

Acceptable sources are:

• a .gwf-format framefile (string ending in '.gwf')
• a LAL-format cache file (string ending in '.lcf' or '.cache')
• a lal.Cache object (either from SWIG-LAL or GLUE)

Parameters

source	input source, see above for details
channel	string name of channel, e.g. 'L1:LDAS-STRAIN', or a list of channel names
start	LIGOTimeGPS start time for output TimeSeries
duration	float duration (seconds) for output TimeSeries
datatype	datatype, either an integer from the LALTYPECODE, a string matchine the corresponding type, or a numpy dtype
verbose	print verbose output, default: False

Returns

a TimeSeries of the imported data

Example 1, reading from a frame file:

>>> out = read_timeseries('L-R-1061499968-32.gwf', 'L1:PSL-ISS_PDB_OUT_DQ')
>>> print(type(out))
<type 'REAL4TimeSeries'>
>>> print(out.name, float(out.epoch), out.deltaT)
('L1:PSL-ISS_PDB_OUT_DQ', 1061499968.0, 3.0517578125e-05)

Example 2, reading from a cache:

>>> import lal
>>> cache = lal.CacheGlob('/scratch/ER4/L0/L1/L-R-10614', 'L-R-1061499968*')
>>> out = frread.read_timeseries(cache, 'L1:PSL-ISS_PDB_OUT_DQ')
>>> print(out.name, float(out.epoch), out.deltaT)
('L1:PSL-ISS_PDB_OUT_DQ', 1061499968.0, 3.0517578125e-05)

Example 3, restricting data input:

>>> out = read_timeseries('L-R-1061499968-32.gwf', 'L1:PSL-ISS_PDB_OUT_DQ',
                          start=1061499970, duration=10)
>>> print(out.name, float(out.epoch), out.data.length)
('L1:PSL-ISS_PDB_OUT_DQ', 1061499970.0, 327680)

Example 4, specifying data type:

>>> out = read_timeseries('L-R-1061499968-32.gwf',
                          'L1:PSL-ODC_CHANNEL_OUT_DQ')
>>> print(type(out), out.data.data[:4])
(<type 'REAL4TimeSeries'>,
 array([ 4259839.,  4259839.,  4259839.,  4259839.], dtype=float32))
>>> out = read_timeseries('L-R-1061499968-32.gwf',
                          'L1:PSL-ODC_CHANNEL_OUT_DQ', datatype='int8')
>>> print(type(out), out.data.data[:4])
(<type 'INT8TimeSeries'>, array([4259839, 4259839, 4259839, 4259839]))

Definition at line 120 of file frread.py.

read_channel_from_stream()

def lalframe.frread.read_channel_from_stream	(		stream,
			channel,
			start,
			duration,
			datatype = None
	)

Read the TimeSeries of a single channel from an open stream.

Definition at line 255 of file frread.py.

get_stream_length()

def lalframe.frread.get_stream_length	(		stream,
			channel
	)

Find the number of samples represented in a frame stream.

Parameters

stream	XLALFrStream() of data to measure
channel	string name of channel to measure

Returns

the integer length of the data for this channel

Definition at line 289 of file frread.py.

get_stream_duration()

def lalframe.frread.get_stream_duration

(

stream

)

Find the duration of time stored in a frame stream.

Parameters

stream

XLALFrStream() of data to measure

Returns

the float duration (seconds) of the data for this channel

Definition at line 312 of file frread.py.