.. _GPAW Calculator Interface:

GPAW Calculator Interface
=========================

:func:`ciderpress.gpaw.calculator.get_cider_functional` loads a mapped model,
validates its feature support and XC composition, and constructs the matching
GGA or meta-GGA smooth-grid/PAW object.  Exchange models receive their
``xmix``, ``xkernel``, and ``ckernel`` composition.  Full-XC models receive the
composition stored in the model.

:class:`ciderpress.gpaw.calculator.CiderGPAW` extends the classic ``GPAW``
calculator with the ability to save a CIDER checkpoint state.
The dictionary of the checkpoint state stores the mapped model text, XC composition,
NLDF interpolation parameters, and PASDW (PAW corrections to nonlocal features)
options needed to reconstruct the functional during restart. This allows
CIDER calculations to be saved to disk and then restarted just like
calculations with other functionals.

.. code-block:: python

    from ciderpress.gpaw.calculator import CiderGPAW, get_cider_functional

    xc = get_cider_functional(
        "CIDER26XCSURFSCI", xmix=1.0, xkernel=None, ckernel=None)
    atoms.calc = CiderGPAW(xc=xc, ...)
    atoms.get_potential_energy()

For a full example, see :source:`examples/gpaw/production_calc.py`
and :doc:`../../usage/gpaw`.

.. automodule:: ciderpress.gpaw.calculator
    :members: