.. include:: autodoc_abbr_options_c.rst

Notes on Options
================

.. note:: The options referred to in the :ref:`sec:methods` section below
   and indexed in :ref:`apdx:options_c_module` are placed in ``set`` blocks as
   described in :ref:`sec:jobControl`, not as arguments to a Python function
   (like ``energy()``).

.. note:: All |PSIfour| keyword names and values are insensitive to case, both
   those that are placed in ``set`` blocks and as Python function arguments.
   The few exceptions are documented for the :py:func:`~wrapper_database.database` function,
   where case structure must match the database file.

.. _`op_c_bool`:
.. _`op_c_boolean`:
.. note:: Boolean options can be specified by ``yes``, ``on``, ``true``, or ``1``
    for affirmative and ``no``, ``off``, ``false``, or ``0`` for negative,
    all insensitive to case.

.. _`op_c_conv`:
.. note:: Certain convergence and tolerance keywords, of type *double* (real numbers),
   may be specified using either a real number or an integer; and integer *X* is then
   treated as the number of converged decimal digits required. For example, to request
   as energy converged to :math:`10^{-6} E_h`, the user may set the ``e_convergence``
   keyword to 0.000001, 1.0e-6, or 6.


Alternate Implementations
=========================

Depending on the reference (RHF, UHF, ROHF) and the integral treatment
(conventional CONV, density-fitted DF, and Cholesky-decomposed CD),
computational methods are sometimes implemented by multiple coders or even
multiple times. |PSIfour| transparently selects the most efficient
implementation, so one generally needn't consult this table. However, to
understand the details of what combinations are accessible or what
alternate implementations are available, read on.

Below, "Y" means method available in module, "D" means module is default
for that method, and "" means method not available. HF, DFT, and MP2
default to density-fitted integrals, while all higher methods default to
conventional integrals. Therefore, for a closed-shell molecule:

* runs MP2 with default ``DF`` with default implementation :ref:`DFMP2 <sec:dfmp2>` ::

    energy('mp2')

* runs MP2 with ``CONV`` with default implementation :ref:`OCC <sec:occ_nonoo>` ::

    set mp2_type conv
    energy('mp2')

* runs MP2 with default ``DF`` with implementation :ref:`OCC <sec:occ_nonoo>` ::

    set qc_module occ
    energy('mp2')


.. _`table:managedmethods`:

.. table:: Overlapping capabilities of |PSIfour|

    +----------------------+----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | name                 | |globals__qc_module| | :py:func:`~driver.energy()`                                              | :py:func:`~driver.gradient()`                                |
    +                      +                      +------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | _                    | |scf__reference|     | RHF                    | UHF                    | ROHF                   | RHF                | UHF                | ROHF               |
    +                      +                      +------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | type select [#f1]_   | _                    | CV   | DF       | CD   | CV   | DF       | CD   | CV       | DF   | CD   | CV   | DF   | CD   | CV   | DF   | CD   | CV   | DF   | CD   |
    +======================+======================+======+==========+======+======+==========+======+==========+======+======+======+======+======+======+======+======+======+======+======+
    | .. _tlmp2:           | CCENERGY             |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | mp2                  | DETCI                | Y    |          |      |      |          |      | Y        |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | |globals__mp2_type|  | DFMP2                |      | D [#f2]_ |      |      | D [#f2]_ |      |          | D    |      |      | D    |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | FNOCC                | Y    |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | OCC                  | D    | Y        | D    | D    | Y        | Y    | D        | Y    | D    | D    | Y    |      | D    | D    |      |      |      |      |
    +----------------------+----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | .. _tlmp3:           | CCENERGY             |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | mp3                  | DETCI                | Y    |          |      |      |          |      | Y [#f3]_ |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | |globals__mp_type|   | DFMP2                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | FNOCC                | Y    |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | OCC                  | D    | D        | D    | D    | D        | D    |          |      |      | D    | D    |      | D    | D    |      |      |      |      |
    +----------------------+----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | .. _tlmp25:          | CCENERGY             |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | mp2.5                | DETCI                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | |globals__mp_type|   | DFMP2                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | FNOCC                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | OCC                  | D    | D        | D    | D    | D        | D    |          |      |      | D    | D    |      | D    | D    |      |      |      |      |
    +----------------------+----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | .. _tlmp4:           | CCENERGY             |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | mp4                  | DETCI                | Y    |          |      |      |          |      | Y [#f3]_ |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | |globals__mp_type|   | DFMP2                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | FNOCC                | D    |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | OCC                  |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +----------------------+----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | .. _tllccd:          | CCENERGY             |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | lccd                 | DETCI                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | |globals__cc_type|   | DFMP2                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | FNOCC                | D    |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | OCC                  | Y    | D        | D    | D    | D        | D    |          |      |      | D    | D    |      | D    | D    |      |      |      |      |
    +----------------------+----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | .. _tllccsd:         | CCENERGY             |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | lccsd, cepa(0)       | DETCI                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | |globals__cc_type|   | DFMP2                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | FNOCC                | D    |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | OCC                  |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +----------------------+----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | .. _tlccsd:          | CCENERGY             | D    |          |      | D    |          |      | D        |      |      | D    |      |      | D    |      |      | D    |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | ccsd                 | DETCI                | Y    |          |      |      |          |      | Y        |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | |globals__cc_type|   | DFMP2                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | FNOCC                | Y    | D        | D    |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | OCC                  |      | Y        | Y    |      |          |      |          |      |      |      | D    |      |      |      |      |      |      |      |
    +----------------------+----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | .. _tlccsdt:         | CCENERGY             | D    |          |      | D    |          |      | D        |      |      |      |      |      | D    |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | ccsd(t)              | DETCI                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | |globals__cc_type|   | DFMP2                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | FNOCC                | Y    | D        | D    |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | OCC                  |      | Y        | Y    |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +----------------------+----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | .. _tlccsdat:        | CCENERGY             | D    |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | ccsd(at)             | DETCI                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | |globals__cc_type|   | DFMP2                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | FNOCC                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | OCC                  |      | D        | D    |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +----------------------+----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | .. _tlcisd:          | CCENERGY             |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | cisd                 | DETCI                | Y    |          |      |      |          |      | D        |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    | |globals__ci_type|   | DFMP2                |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | FNOCC                | D    |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +                      +----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+
    |                      | OCC                  |      |          |      |      |          |      |          |      |      |      |      |      |      |      |      |      |      |      |
    +----------------------+----------------------+------+----------+------+------+----------+------+----------+------+------+------+------+------+------+------+------+------+------+------+

.. rubric:: Footnotes

.. [#f1] Algorithm type selection keyword below. Values to the right: conventional ``CONV`` (here abbreviated CV), density-fitted ``DF``, and Cholesky-decomposed ``CD``.
.. [#f2] Also available for KS reference.
.. [#f3] Conditions have *no* default module (computationally inefficient) and can only be accessed by specifying |globals__qc_module|.