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

.. only:: html

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

        Click :ref:`here <sphx_glr_download_gallery_plot_qha_vs_qmesh.py>`
        to download the full example code or to run this example in your browser via Binder

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

.. _sphx_glr_gallery_plot_qha_vs_qmesh.py:


Quasi-harmonic approximation (convergence wrt Q-mesh)
=====================================================

This example shows how to use the GSR.nc and PHDOS.nc files computed with different volumes
to analyze the convergence of QHA thermodynamic properties with respect to the number of q-points
used to compute the phonon DOS.

.. GENERATED FROM PYTHON SOURCE LINES 10-39



.. rst-class:: sphx-glr-horizontal


    *

      .. image:: /gallery/images/sphx_glr_plot_qha_vs_qmesh_001.png
          :alt: Energies as a function of volume for different T, ngpqt: [2 2 2], ngpqt: [4 4 4]
          :class: sphx-glr-multi-img

    *

      .. image:: /gallery/images/sphx_glr_plot_qha_vs_qmesh_002.png
          :alt: Thermal expansion coefficient as a function of T
          :class: sphx-glr-multi-img

    *

      .. image:: /gallery/images/sphx_glr_plot_qha_vs_qmesh_003.png
          :alt: Volume as a function of T
          :class: sphx-glr-multi-img


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

 Out:

 .. code-block:: none


    <Figure size 640x480 with 1 Axes>





|

.. code-block:: default

    import os
    import abipy.data as abidata

    from abipy.dfpt.qha import QHAQmeshAnalyzer

    # We use a list of GSR.nc and PHDOS.nc files corresponding to different isotropic strains.
    # These files are shipped with AbiPy so that we don't need to run calculations from scratch.
    #strains = [-4, -2, 0, 2, 4, 6]
    strains = [-2, 0, 2, 4]
    dirpath = os.path.join(abidata.dirpath, "refs", "si_qha")

    gsr_paths = [os.path.join(dirpath, "mp-149_{:+d}_GSR.nc".format(s)) for s in strains]
    ddb_paths = [os.path.join(dirpath, "mp-149_{:+d}_DDB".format(s)) for s in strains]

    # Initialize QHA object from files.
    qhana = QHAQmeshAnalyzer(gsr_paths, ddb_paths)

    # To change the default EOS (vinet), use
    #qhana.set_eos("vinet")

    # Compute ph-DOS with this list of nqsmall values.
    qhana.run_qlist([2, 4])

    # Analyze convergence. API similar to QHA.
    qhana.plot_energies(title="Energies as a function of volume for different T")

    qhana.plot_thermal_expansion_coeff(title="Thermal expansion coefficient as a function of T")

    qhana.plot_vol_vs_t(title="Volume as a function of T")


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

   **Total running time of the script:** ( 0 minutes  19.360 seconds)


.. _sphx_glr_download_gallery_plot_qha_vs_qmesh.py:


.. only :: html

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


  .. container:: binder-badge

    .. image:: images/binder_badge_logo.svg
      :target: https://mybinder.org/v2/gh/abinit/abipy/gh-pages?filepath=notebooks/gallery/plot_qha_vs_qmesh.ipynb
      :alt: Launch binder
      :width: 150 px


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

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



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

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


.. only:: html

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

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