.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "examples/spectrogram/coherencegram.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_examples_spectrogram_coherencegram.py>`
        to download the full example code.

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_examples_spectrogram_coherencegram.py:


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

Calculating the time-dependent coherence between two channels
#############################################################

The standard coherence calculation outputs a frequency series
(`~gwpy.frequencyseries.FrequencySeries`) giving a time-averaged measure
of coherence. See :ref:`sphx_glr_examples_frequencyseries_coherence.py` for an
example.

The `TimeSeries` method :meth:`~TimeSeries.coherence_spectrogram` performs the
same coherence calculation every ``stride``, giving a time-varying coherence
measure.

These data are available as part of the |GWOSC_AUX_RELEASE|_.

.. GENERATED FROM PYTHON SOURCE LINES 39-40

First, we import the `TimeSeriesDict`

.. GENERATED FROM PYTHON SOURCE LINES 40-42

.. code-block:: Python

    from gwpy.timeseries import TimeSeriesDict








.. GENERATED FROM PYTHON SOURCE LINES 43-46

and then :meth:`~TimeSeriesDict.get` the data for the differential-arm
length servo control loop error signal (``H1:LSC-DARM_IN1_DQ``) and the
PSL periscope accelerometer (``H1:PEM-CS_ACC_PSL_PERISCOPE_X_DQ``):

.. GENERATED FROM PYTHON SOURCE LINES 46-55

.. code-block:: Python

    data = TimeSeriesDict.get(
        ["H1:LSC-DARM_IN1_DQ", "H1:PEM-CS_ACC_PSL_PERISCOPE_X_DQ"],
        1186741560,
        1186742160,
        host="nds.gwosc.org",
    )
    darm = data["H1:LSC-DARM_IN1_DQ"]
    acc = data["H1:PEM-CS_ACC_PSL_PERISCOPE_X_DQ"]





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    /home/duncan.macleod/gwpy-nightly-build/conda/envs/gwpy-nightly-3.11/lib/python3.11/site-packages/igwn_auth_utils/requests.py:46: DeprecationWarning: Support for identity-based X.509 credentials for LIGO.ORG is being dropped.
    Calls to this utility will stop working on/around 20 May 2025.

    For details on this change please see

    https://computing.docs.ligo.org/guide/compsoft/roadmap/LVK/x509_retirement/

    If you have questions about this message, or its implications, please
    consider opening an IGWN Computing Help Desk ticket:

    https://git.ligo.org/computing/helpdesk/-/issues/new
      return func(*args, **kwargs)




.. GENERATED FROM PYTHON SOURCE LINES 56-59

We can then calculate the :meth:`~TimeSeries.coherence` of one
`TimeSeries` with respect to the other, using an 2-second Fourier
transform length, with a 1-second (50%) overlap:

.. GENERATED FROM PYTHON SOURCE LINES 59-61

.. code-block:: Python

    coh = darm.coherence_spectrogram(acc, 10, fftlength=.5, overlap=.25)








.. GENERATED FROM PYTHON SOURCE LINES 62-64

Finally, we can :meth:`~gwpy.spectrogram.Spectrogram.plot` the
resulting data

.. GENERATED FROM PYTHON SOURCE LINES 64-75

.. code-block:: Python

    plot = coh.plot()
    ax = plot.gca()
    ax.set_ylabel("Frequency [Hz]")
    ax.set_yscale("log")
    ax.set_ylim(10, 2000)
    ax.set_title(
        "Coherence between PSL periscope motion and LIGO-Hanford strain data",
    )
    ax.grid(visible=True, which="both", axis="both")
    ax.colorbar(label="Coherence", clim=[0, 1], cmap="plasma")
    plot.show()



.. image-sg:: /examples/spectrogram/images/sphx_glr_coherencegram_001.png
   :alt: Coherence between PSL periscope motion and LIGO-Hanford strain data
   :srcset: /examples/spectrogram/images/sphx_glr_coherencegram_001.png
   :class: sphx-glr-single-img






.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 4.170 seconds)


.. _sphx_glr_download_examples_spectrogram_coherencegram.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: coherencegram.ipynb <coherencegram.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: coherencegram.py <coherencegram.py>`

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: coherencegram.zip <coherencegram.zip>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_