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

.. only:: html

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

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

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

.. _sphx_glr_flow_gallery_run_eph_qpath.py:


e-ph matrix elements along q-path
=================================

This example demonstrates how to compute electron-phonon (e-ph) matrix elements
along a specified q-path, either by explicitly calculating the self-consistent potential perturbations
(Δq Vscf) for each q-point using ab initio methods, o
r by employing Fourier interpolation techniques starting from a coarse q-point mesh.

.. GENERATED FROM PYTHON SOURCE LINES 11-111



.. image-sg:: /flow_gallery/images/sphx_glr_run_eph_qpath_001.png
   :alt: run eph qpath
   :srcset: /flow_gallery/images/sphx_glr_run_eph_qpath_001.png
   :class: sphx-glr-single-img





.. code-block:: Python

    import sys
    import os
    import abipy.abilab as abilab
    import abipy.data as abidata

    from abipy import flowtk
    from abipy.flowtk.eph_flows import EphPotFlow


    def build_flow(options):

        # Working directory (default is the name of the script with '.py' removed and "run_" replaced by "flow_")
        if not options.workdir:
            options.workdir = os.path.basename(sys.argv[0]).replace(".py", "").replace("run_", "flow_")

        # Build input for GS calculation
        # Fe BCC structure
        structure = abilab.Structure.from_abistring("""
    natom 1
    ntypat 1
    typat  1
    znucl 26

    acell 3*5.201879033248
    rprim  0.5  0.5  0.5   # BCC primitive vectors (to be scaled by acell)
          -0.5  0.5  0.5
          -0.5 -0.5  0.5
    xred 3*0
    """)

        pseudos = abidata.pseudos("Fe.psp8")
        #pseudos = abidata.pseudos("Fe.upf")
        scf_input = abilab.AbinitInput(structure, pseudos=pseudos)
        num_ele = scf_input.num_valence_electrons

        scf_input.set_vars(
            ecut=50,
            nsppol=2,
            spinat=[0, 0, 6.0],
            nband=12,
            occopt=7,
            tsmear=0.0025,
            tolvrs=6.075e-16,
            nstep=300,
            paral_kgb=0,
            vloc_rcut=10,
            #toldfe1=5e-13,
            #ngfft=[30, 30, 30],
        )

        # K-point grid
        #scf_input.set_kmesh(ngkpt=[24, 24, 24], shiftk=[0, 0, 0])
        scf_input.set_kmesh(ngkpt=[2, 2, 2], shiftk=[0, 0, 0])

        # q-mesh for phonons.
        ngqpt = [2, 2, 2]
        #ngqpt = [1, 1, 1]

        # Lisg of q-points in reduced coordinates.
        qpath_list = [
            +0.10000,  +0.10000,  +0.10000,
            +0.00000,  +0.00000,  +0.00000,
            +0.10000,  +0.00000,  +0.10000,
        ]

        flow = EphPotFlow.from_scf_input(
            options.workdir,
            scf_input,
            ngqpt,
            qpath_list,
            ndivsm=0,                     # pass full list of q-points instead of boundaries.
            what_to_compute="gkq_qpath",  # Important!
            with_becs=False,              # Metal --> no becs, no dynamical quadrupoles.
            with_quad=False,
        )

        return flow


    # This block generates the thumbnails in the Abipy gallery.
    # You can safely REMOVE this part if you are using this script for production runs.
    if os.getenv("READTHEDOCS", False):
        __name__ = None
        import tempfile
        options = flowtk.build_flow_main_parser().parse_args(["-w", tempfile.mkdtemp()])
        build_flow(options).graphviz_imshow()


    @flowtk.flow_main
    def main(options):
        """
        This is our main function that will be invoked by the script.
        flow_main is a decorator implementing the command line interface.
        Command line args are stored in `options`.
        """
        return build_flow(options)


    if __name__ == "__main__":
        sys.exit(main())


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

   **Total running time of the script:** (0 minutes 4.782 seconds)


.. _sphx_glr_download_flow_gallery_run_eph_qpath.py:

.. only:: html

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

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

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

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

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

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

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


.. only:: html

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

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