.. sectionauthor:: Duncan Macleod <duncan.macleod@ligo.org>

.. currentmodule:: gwpy.table.lsctables

Plotting event rate for specific column bins
############################################

I would like to study the rate at which event triggers are generated by the
`ExcessPower` gravitational-wave burst detection algorithm, over a small
stretch of data, binned by various thresholds on signal-to-noise ratio (SNR).

The data from which these events were generated are a simulation of Gaussian noise
with the Advanced LIGO design spectrum, and so don't actually contain any real
gravitational waves, but will help tune the algorithm to improve detection of
future, real signals.




First, we import the `SnglBurstTable` and read the events

.. code-block:: python

   from gwpy.table.lsctables import SnglBurstTable
   events = SnglBurstTable.read('../../gwpy/tests/data/H1-LDAS_STRAIN-968654552-10.xml.gz')


Now we can use the :math:`~SnglBurstTable.binned_event_rates` method to calculated the event rate in a number of bins of SNR.

.. code-block:: python

   rates = events.binned_event_rates(1, 'snr', [2, 3, 5, 8], operator='>=',
                                     start=968654552, end=968654562)

.. note::

   The list `[2, 3, 5, 8]` and operator `>=` specifies SNR tresholds of 
   2, 3, 5, and 8.

Finally, we can make a plot:

.. code-block:: python

   plot = rates.plot(label='name')
   plot.set_xlim(968654552, 968654562)
   plot.set_ylabel('Event rate [Hz]')
   plot.set_title('LIGO Hanford Observatory event rate for GW100916')
   plot.add_legend()
   plot.show()

.. plot:: ../examples/table/rate_binned.py