From 8883915839e8d85b6110c34208fb34b809a8426b Mon Sep 17 00:00:00 2001
From: Colm Talbot <colm.talbot@ligo.org>
Date: Tue, 5 Jun 2018 15:31:19 +1000
Subject: [PATCH] add basic frame reading function
---
tupak/utils.py | 106 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 106 insertions(+)
diff --git a/tupak/utils.py b/tupak/utils.py
index 6b6f575ae..381265541 100644
--- a/tupak/utils.py
+++ b/tupak/utils.py
@@ -4,6 +4,8 @@ import os
import numpy as np
from math import fmod
from gwpy.timeseries import TimeSeries
+from gwpy.signal import filter_design
+from scipy import signal
import argparse
# Constants
@@ -514,6 +516,110 @@ def get_open_strain_data(
return strain
+def read_frame_file(file_name, t1, t2, channel=None, **kwargs):
+ """ A function which accesses the open strain data
+
+ This uses `gwpy` to download the open data and then saves a cached copy for
+ later use
+
+ Parameters
+ ----------
+ file_name: str
+ The name of the frame to read
+ t1, t2: float
+ The GPS time of the start and end of the data
+ channel: str
+ The name of the channel being searched for, some standard channel names are attempted
+ if channel is not specified or if specified channel is not found.
+ **kwargs:
+ Passed to `gwpy.timeseries.TimeSeries.fetch_open_data`
+
+ Returns
+ -----------
+ strain: gwpy.timeseries.TimeSeries
+
+ """
+ loaded = False
+ if channel is not None:
+ try:
+ strain = TimeSeries.read(source=file_name, channel=channel, start=t1, end=t2, **kwargs)
+ loaded = True
+ logging.info('Successfully loaded {}.'.format(channel))
+ except RuntimeError:
+ logging.warning('Channel {} not found. Trying preset channel names'.format(channel))
+ for channel in ['GDS-CALIB_STRAIN', 'DCS-CALIB_STRAIN_C01', 'DCS-CALIB_STRAIN_C02']:
+ if loaded:
+ continue
+ try:
+ strain = TimeSeries.read(source=file_name, channel=channel, start=t1, end=t2, **kwargs)
+ loaded = True
+ logging.info('Successfully loaded {}.'.format(channel))
+ except RuntimeError:
+ None
+
+ if loaded:
+ return strain
+ else:
+ logging.warning('No data loaded.')
+ return None
+
+
+def process_strain_data(
+ strain, alpha=0.25, filter_freq=1024, **kwargs):
+ """
+ Helper function to obtain an Interferometer instance with appropriate
+ PSD and data, given an center_time.
+
+ Parameters
+ ----------
+ name: str
+ Detector name, e.g., 'H1'.
+ center_time: float
+ GPS time of the center_time about which to perform the analysis.
+ Note: the analysis data is from `center_time-T/2` to `center_time+T/2`.
+ T: float
+ The total time (in seconds) to analyse. Defaults to 4s.
+ alpha: float
+ The tukey window shape parameter passed to `scipy.signal.tukey`.
+ psd_offset, psd_duration: float
+ The power spectral density (psd) is estimated using data from
+ `center_time+psd_offset` to `center_time+psd_offset + psd_duration`.
+ outdir: str
+ Directory where the psd files are saved
+ plot: bool
+ If true, create an ASD + strain plot
+ filter_freq: float
+ Low pass filter frequency
+ **kwargs:
+ All keyword arguments are passed to
+ `gwpy.timeseries.TimeSeries.fetch_open_data()`.
+
+ Returns
+ -------
+ interferometer: `tupak.detector.Interferometer`
+ An Interferometer instance with a PSD and frequency-domain strain data.
+
+ """
+
+ sampling_frequency = int(strain.sample_rate.value)
+
+ # Low pass filter
+ bp = filter_design.lowpass(filter_freq, strain.sample_rate)
+ strain = strain.filter(bp, filtfilt=True)
+ strain = strain.crop(*strain.span.contract(1))
+
+ time_series = strain.times.value
+ time_duration = time_series[-1] - time_series[0]
+
+ # Apply Tukey window
+ N = len(time_series)
+ strain = strain * signal.windows.tukey(N, alpha=alpha)
+
+ frequency_domain_strain = nfft(strain.value, sampling_frequency)[0]
+
+ return frequency_domain_strain
+
+
def set_up_command_line_arguments():
parser = argparse.ArgumentParser(
description="Command line interface for tupak scripts")
--
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