PyFstat

This is a python package providing an interface to perform F-statistic based continuous gravitational wave (CW) searches. At its core, this is a simple wrapper of selected tools in 'lalpulsar'. The general idea is to allow easy scripting of new search pipelines, we focus primarily on interfacing the CW routines with emcee a python MCMC sampler.

Examples

We include a variety of example search scripts here, for each example there is also a more descriptive write-up containing examples of the output which we list below. Before running any of the search examples, be sure to have run the script to generate fake data.

• Making fake data with and without glitches
• Fully-coherent MCMC search
• Fully-coherent MCMC search on data containing a single glitch
• Semi-coherent MCMC glitch-search on data containing a single glitch
• Semi-coherent MCMC glitch-search on data containing two glitches
• Semi-coherent Follow-Up MCMC search (dynamically changing the coherence time)

Installation

python installation

The scripts are written in python 2.7+ and therefore require a working python installation. While many systems come with a system wide python installation, it can often be easier to manage a user-specific python installation. This way one does not require root access to install or remove modules. One method to do this, is to use the conda system, either through the stripped down miniconda installation, or the full-featured anaconda (these are essentially the same, but the anaconda version installs a variety of useful packages such as numpy and scipy by default.

pyfstat installation

The script can be installed system wide via

$ python setup.py install

or simply add this directory to your python path. To check that the installation was successful, run

$ python -c 'import pyfstat'

if no error message is output, then you have installed pyfstat. Note that the module will be installed to whichever python executable you call it from.

Ephemeris installation

The scripts require a path to ephemeris files in order to use the lalpulsar.ComputeFstat module. This can either be specified when initialising each search, or more simply by placing a file ~/.pyfstat.conf into your home directory which looks like

earth_ephem = '/home/<USER>/lalsuite-install/share/lalpulsar/earth00-19-DE421.dat.gz'
sun_ephem = '/home/<USER>/lalsuite-install/share/lalpulsar/sun00-19-DE421.dat.gz'

here, we use the default ephemeris files provided with lalsuite.

Dependencies

The installation above will complete succesfully without the following dependencies, but you will subsequently find various ImportError messages when running pyfstat scripts if you haven't installed the following modules.

• swig-enabled lalapps with at least lalpulsar. A minimal confuration line to use when installing lalapps is

$ ./configure --prefix=${HOME}/lalsuite-install --disable-all-lal --enable-lalpulsar --enable-lalapps --enable-swig

• If using the MCMC tools, you will need to install the following python modules

  • numpy
  • scipy
  • emcee
  • corner
  • dill
  • tqdm(optional), if installed, this provides a useful progress bar and estimate of the remaining run-time.

  To install all of these modules, run

$ pip install -r /PATH/TO/THIS/DIRECTORY/requirements.txt

where pip is the python package installer, if you have installed python from conda then it can be installed via conda install pip.